The present disclosure generally relates to an input power supply circuit for a motor controller of an electric motor. More specifically, the present disclosure relates to a brushless DC electric motor (BLDC) motor controller used in fuel pump modules in vehicles.
BACKGROUND
[0002] In the fuel pump, there is a motor which pumps the fuel and sends the pressurized fuel from a fuel tank to an injector. The main functional parameters decided by the motor are fuel flow rate and its pressure. For the working of the motor, electrical energy is converted into mechanical energy. For the supply of electrical energy in the motor, one motor controller is mounted on the fuel pump.
[0003] Currently in the fuel pumps present in the market, the motor controller directly runs the motor at a constant Revolutions Per Minute (RPM) and it doesn't have any functionality to run the motor at the variable RPM. Further, in the presently available motors, there is no protection against the surge voltage, which is generally generated due to various circuit-level switching of power signals at system-level. There are no preventive measures that can protect the motor controller and other passive electronic components of the motor. Non-availability of such preventive measures may lead to malfunctioning of the motor controller of the motor and thus may lead to non-operation of the fuel pump.
[0004] Further, the currently available motor also does not provide preventive measures to take care of voltage drop issues, which may arise due to excess current drawn by the vehicle. In this scenario, the motor controller might not get sufficient voltage to operate the motor due to which the fuel supply to the vehicle may get affected.

[0005] Thus, there exists a need for the improvement of technology where the motor and its motor controller may be protected against the voltage surges, and the voltage undershoots are taken care of. There is also a need to provide the capability to the motor controller to run the motor at a variable RPM.
SUMMARY
[0006] The present disclosure overcomes one or more shortcomings of the prior art and provides additional advantages. Embodiments and aspects of the disclosure described in detail herein are considered a part of the claimed disclosure.
[0007] In one non-limiting embodiment of the present disclosure, a power supply circuit for a motor controller of a motor is disclosed. The power supply circuit comprises a Pulse Width Modulation (PWM) signal input to receive a PWM signal for the motor controller to control speed of the motor. The power supply circuit further comprises a voltage surge protection diode, coupled between the motor controller and an input terminal of the power supply circuit in parallel connection, to bypass excess voltage at the input terminal to a ground terminal of the power supply circuit by connecting the input terminal with the ground terminal, when the voltage at the input terminal is greater than a pre-defined upper threshold. The power supply circuit furthermore comprises a pair of voltage regulation capacitors, coupled between the motor controller and the input terminal of the power supply circuit in the parallel connection, to maintain a supply voltage for the motor controller at a fixed value by way of discharging, when the voltage available at the input terminal of the power supply circuit is less than a pre-defined lower threshold.
[0008] In another non-limiting embodiment of the present disclosure, wherein the speed of the motor is controlled by changing a duty cycle of the PWM signal.
[0009] In yet another non-limiting embodiment of the present disclosure, a negative terminal of the voltage surge protection diode is coupled with the input

terminal of the power supply circuit and a positive terminal of the voltage surge protection diode is coupled with the ground terminal of the power supply circuit.
[0010] In yet another non-limiting embodiment of the present disclosure, the power supply circuit further comprises an electrostatic discharge protection capacitor, coupled between the motor controller and the input terminal of the power supply circuit in the parallel connection, to provide protection against electrostatic discharge.
[0011] In yet another non-limiting embodiment of the present disclosure, the power supply circuit further comprises a reverse voltage protection unit, coupled between the motor controller and the input terminal of the power supply circuit to provide protection against reverse voltage, wherein a first terminal of the reverse voltage protection unit is coupled with the motor controller, a second terminal of the reverse voltage protection unit is coupled with the input terminal of the power supply circuit, and a third terminal of the reverse voltage protection unit is coupled with the ground terminal.
[0012] In yet another non-limiting embodiment of the present disclosure, a method of operating a power supply circuit for a motor controller of a motor is disclosed. The method comprises receiving a Pulse Width Modulation (PWM) signal to control speed of the motor. The method further comprises bypassing, via a voltage surge protection diode coupled between the motor controller and an input terminal of the power supply circuit in parallel connection, excess voltage at an input terminal of the power supply circuit to a ground terminal of the power supply circuit by connecting the input terminal with the ground terminal, when the voltage at the input terminal is greater than a pre-defined upper threshold. Further, the method comprises maintaining, via a pair of voltage regulation capacitors coupled between the motor controller and the input terminal of the power supply circuit in the parallel connection, a supply voltage for the motor controller at a fixed value by way of discharging, when the voltage at the input terminal of the power supply circuit is less than a pre-defined lower threshold.

[0013] In yet another non-limiting embodiment of the present disclosure, the speed of the motor is controlled by changing a duty cycle of the PWM signal.
[0014] In yet another non-limiting embodiment of the present disclosure, a negative terminal of the voltage surge protection diode is coupled with the input terminal of the power supply circuit and a positive terminal of the voltage surge protection diode is coupled with the ground terminal of the power supply circuit.
[0015] In yet another non-limiting embodiment of the present disclosure, the method further comprises providing protection against electrostatic discharge via an electrostatic discharge protection capacitor coupled between the motor controller and the input terminal of the power supply circuit in the parallel connection.
[0016] In yet another non-limiting embodiment of the present disclosure, the method further comprises providing protection against reverse voltage via a reverse voltage protection unit coupled between the motor controller and the input terminal of the power supply circuit, wherein a first terminal of the reverse voltage protection unit is coupled with the motor controller, a second terminal of the reverse voltage protection unit is coupled with the input terminal of the power supply circuit, and a third terminal of the reverse voltage protection unit is coupled with the ground terminal.
[0017] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
OBJECTIVES OF THE INVENTION
[0018] An object of the present disclosure is to enable an electric motor to operate at a variable RPM with the help of PWM input.

[0019] Another object of the present disclosure is to provide electrical protection for sudden voltage surge pulses.
[0020] Yet another object of the present disclosure is to provide sufficient voltage to operate the motor in case of voltage undershoots.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed embodiments. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:
[0022] Fig. 1 illustrates a block diagram of a system having a power supply circuit for a motor controller to provide protection against a surge in voltage and voltage undershoot, and operate the motor at variable RPM, according to an aspect of the present invention.
[0023] FIG. 2 illustrates a power supply circuit for a motor controller to provide protection against a surge in voltage and voltage undershoot, and operate the motor at variable RPM, according to an aspect of the present invention.
[0024] FIG. 3 illustrates a flowchart of a method of operating a power supply circuit for a motor controller of a motor to provide protection against a surge in voltage and voltage undershoot, and operate the motor at variable RPM, according to an aspect of the present invention.

[0025] It should be appreciated by those skilled in the art that any block diagrams and circuit diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter.
DETAILED DESCRIPTION
[0026] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject-matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
[0027] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
[0028] The terms "comprises", "comprising", "include(s)", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, system or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or system or method. In other words, one or more elements in a system or apparatus proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[0029] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail

to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
[0030] The present invention will be described herein below with reference to the accompanying drawings. In the following description, well known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.
[0031] The present invention relates to an input power supply circuit for a BLDC motor controller which may provide protection against surges in voltage, handle undershoot in the voltage, and which may operate the motor at variable RPM. The disclosed power supply circuit enables the motor controller to operate the motor at the variable RPM, which may be helpful in case of minor or major BLDC motor rotor jamming. For example, such jamming may be removed by increasing the RPM of the motor. Further, the power supply circuit provides protection against surge in the voltage, to protect the motor controller and passive electronic components of the motor. Such surge in the voltage may be generated due to various circuit-level switching of power signals at system level and may lead to malfunctioning of the motor controller of the motor. Also, the power supply circuit is able to maintain sufficient voltage when there is a voltage drop due to excess current drawn by the vehicle. In an embodiment, the vehicle may draw excess current during cranking, but not limited thereto. Due to the excess current draw, the motor controller might not get sufficient voltage to operate the motor for some time duration which may range from a few milliseconds to a few seconds, but not limited thereto. The disclosed power supply circuit avoids such interruption in the voltage which may affect the fuel supply to the vehicle. Accordingly, the present disclosure discloses techniques to resolve the mentioned problems and discloses the power supply circuit for the motor controller which

takes care of the surge and the undershoot in the voltage, and which may also operate the motor at the variable RPM.
[0032] Referring to figure 1, an exemplary motor controlling system 100 having an input power supply circuit for providing protection against surge and undershoot in the operating voltage of the motor controller and to control RPM of the motor is disclosed. The system 100 may comprise a motor 102, a motor controller 104 (also herein referred as "controller"), and a power supply circuit 112. In an embodiment, the motor 102 may be a Brushless DC electric motor (BLDC), but not limited thereto. The power supply circuit 112 may comprise a Voltage Surge Control Unit 106, a Voltage Undershoot Control Unit 108, and a Motor RPM Control Unit 110 combinedly forming the input supply circuit. The motor controller 104 may further comprise one or more processors and a memory (not shown in figure 1). In an aspect, various elements/entities of the system 100 may communicate with each other over wired or wireless links. In fig. 1, only one controller is shown only for the sake of ease and should not be construed as limiting the scope and multiple controllers may be present in the system 100. It must be understood to the skilled person that system 100 shown in figure 1 is for purpose of example only. Further, there may be 'n' number of other components which the system 100 of the present disclosure may comprise and the same are not essential for explaining the scope of the present disclosure and are thus not shown for the sake of brevity.
[0033] According to an exemplary embodiment of the present disclosure, the motor controller 104 may be configured to control the entire operation of the motor i.e., voltage supply to the motor 102 and RPM of the motor 102, switching ON/OFF operations of the motor 102, but not limited thereto. According to an embodiment of the present disclosure, the Voltage Surge Control unit 106 may provide the protection to the motor 102, the controller 104 and other elements which may be present in the system 100 or which may be operationally coupled with the motor 102/controller 104. Particularly, the Voltage Surge Control Unit 106 provides protection against the surge in the voltage, which otherwise may lead

to malfunctioning of the motor 102, the controller 104 and other elements. According to a non-limiting exemplary embodiment, the surge in the voltage may be due to various circuit-level switching of power signals at system-level, but not limited thereto. According to an embodiment of the present disclosure, the Voltage Surge Control Unit 106 may comprise a diode, which clamps the surge voltage pulses up to a voltage level at which system 100 can function properly without getting damaged or getting faulty. In an embodiment, the Voltage Surge Control Unit 106 may bypass the excess voltage to the ground to protect the system 100 from any fault.
[0034] According to another non-limiting exemplary embodiment of the present disclosure, the Voltage Undershoot Control Unit 108 may provide protection to the motor 102, the controller 104 and other elements which may be present in the system 100 or which may be operationally coupled with the motor 102/controller 104. Particularly, the Voltage Undershoot Control unit 108 may provide the protection against a drop in the voltage in the system 100. According to a non-limiting embodiment of the present disclosure, while cranking there may be voltage drop because of the excess current drawn by the vehicle (or the system 100) and due to which the controller 104 might not get sufficient voltage to operate the motor 102 for a short time duration, thus the fuel supply to the vehicle may get affected. In an embodiment, the time duration may range from a few milliseconds to a few seconds, but not limited thereto According to an embodiment of the present disclosure, the Voltage Undershoot Control unit 108 may comprise one or more capacitors to maintain a sufficient voltage during cranking of the vehicle so that fuel supply to the vehicle can be maintained during the cranking of the vehicle.
[0035] According to another non-limiting exemplary embodiment of the present disclosure, the Motor RPM Control Unit 110 may enable the operation of the motor 102 at variable RPM. The Motor RPM Control unit 110 enables the controller to change the RPM of the motor as per the requirements. Further, the Motor RPM Control unit 110 may provide a feature to run the motor 102 at

variable RPM by controlling the RPM of the motor 102. Such control in the change in the RPM of the motor 102 may help in case of minor or major motor rotor jamming by increasing the RPM of the motor 102. In this way, the motor 102 may self-clean itself by operating at higher RPM for few seconds.
[0036] According to an embodiment of the present disclosure, the Motor RPM Control unit 110 may employ pulse width modulation technique to control the RPM of the Motor 102. The unit 110 may comprise a PWM signal input to receive the signals for the Controller 104 to run motor at different RPMs. This helps in self-cleaning of the motor 102 during startup & rotor jamming conditions by moving the motor 102 at a higher RPM compared to its normal functioning RPM. The structure and working of the power supply circuit 112, to achieve the desired objectives of the present disclosure, is explained in detail in forthcoming paragraphs, in conjunction with figure 1 and figure 2.
[0037] Figure 2 discloses a power supply circuit 200 for a motor controller 202 of a motor to provide protection against surge and undershoot in the voltage and for operating the motor at variable speed. In the power supply circuit 200, the motor 102 is not shown. The power supply circuit 200 may comprise a Pulse Width Modulation (PWM) signal input 204 to receive a PWM signal for the motor controller 202 to control the speed of the electric motor. The speed of the motor may be defined in terms of the RPM and thus, the PWM signal may be used to control the RPM of the motor. The speed of the motor may be controlled by the motor controller 202 using the PWM signal. In an embodiment, the speed of the motor may be controlled by changing the duty cycle of the PWM signal. Thus, the duty cycle of the PWM signal may be adjusted to control the speed of the motor as per requirement. The variation in the speed of the motor may be helpful when the motor gets jammed and additional force is required to get rid of the jam. Such additional force may be provided by increasing the speed of the motor. In another example, there may be a requirement for extra fuel supply, which may be easily fulfilled by increasing the speed of the motor. Hence, the ability to change the

speed of the motor as per the requirement may be very useful and such changes in the speed of the motor may be controlled efficiently using the PWM signal.
[0038] The power supply circuit 200 may further comprise a voltage surge protection element 206 to provide protection against voltage surge in the supply voltage being provided to motor controller 202. In an embodiment, the voltage surge protection element may be a Zener diode ("DZ1" in fig. 2). The voltage surge protection diode 206 may be coupled between the motor controller 202 and an input terminal 210 of the power supply circuit 200 in parallel connection in such a manner that the voltage surge protection diode 206 may clamp or bypass voltage at the input terminal 210 to a ground terminal 212 of the power supply circuit 200 by connecting the input terminal 210 with the ground terminal 212, when the voltage at the input terminal 210 is greater than a pre-defined upper threshold. The upper threshold may be the maximum voltage which may be provided to the motor controller 202 without causing any damage to the motor controller 202 and/or other elements of the circuit 200. The voltage surge protection diode 206 may be coupled between the motor controller 202 and the input terminal 210 in the parallel connection such that a negative terminal of the voltage surge protection diode 206 is coupled with the input terminal 210 and a positive terminal of the voltage surge protection diode 206 is coupled with the ground terminal 212 of the power supply circuit 200. In this manner, the voltage surge protection diode 206 may provide protection against the voltage surge in the circuit.
[0039] Furthermore, the power supply circuit 200 may comprise one or more voltage regulation elements 208 to ensure that the motor controller 202 receives sufficient voltage to operate the motor. In an embodiment, the voltage regulation element may be a capacitor which is coupled between the motor controller 202 and the input terminal 210 in the parallel connection to the motor controller 202. The pair of voltage regulation capacitors 208 ("C2" and "C3" in fig. 2) may maintain a supply voltage for the motor controller 202 at a fixed value by discharging the

charge stored therein when the voltage available at the input terminal 210 of the power supply circuit 200 is less than a pre-defined lower threshold. Thus, whenever the supply voltage drops below the lower threshold, the voltage regulation capacitors 208 may discharge to provide sufficient voltage to the motor controller 202 to operate the motor. In an embodiment, the fixed value of the voltage may be a voltage required by the motor controller 202 to operate the motor. In figure 2, there are two capacitors 208a and 208b are shown as the voltage regulation capacitors 208, but there may be more than or less than two capacitors to maintain the supply voltage in case of the voltage undershoot. In an embodiment, the voltage regulation capacitor 208 may be a bulk capacitor, but not limited thereto.
[0040] In an embodiment, the power supply circuit 200 may further comprise an electrostatic discharge protection capacitor 214 ("CI" in fig. 2) which may be coupled between the motor controller 202 and the input terminal 210 of the power supply circuit 200 in the parallel connection. The electrostatic discharge protection capacitor 214 may provide protection against electrostatic discharge in the power supply circuit 200.
[0041] In an embodiment, the circuit 200 may also comprise a reverse voltage protection unit 216 which may be coupled between the motor controller 202 and the input terminal 212 of the power supply circuit 200 to provide protection against reverse voltage. The reverse voltage protection unit 216 may comprise a transistor Ql, diode Dl, and resistor R as shown in fig. 2. The first terminal of the reverse voltage protection unit 216 may be coupled with the motor controller 202, a second terminal of the reverse voltage protection unit 216 may be coupled with the input terminal 212 of the power supply circuit 200, and a third terminal of the unit 216 may be coupled with the ground. In an embodiment, the diode Dl may be a Zener diode, but not limited thereto.

[0042] In this manner, the present disclosure enables the motor to operate at variable RPM with the help of PWM input. In this way, the motor may be self-cleaned by operating at higher RPM for few seconds. Further, the motor controller is also electrically protected for sudden high voltage. Further, the motor controller remains operational in case of sudden decrease in voltage during start & running state. In this way, the RPM of the motor remains stabilized.
[0043] Fig. 3 illustrates a flow chart of a method 300 of operating a power supply circuit for a motor controller of an electric motor, according to an embodiment of the present disclosure. The method 300 may also be described in the general context of computer executable instructions. Generally, computer executable instructions may include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform specific functions or implement specific abstract data types.
[0044] The order in which the method 300 is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the spirit and scope of the subject matter described.
[0045] The method 300, at step 302, may comprise receiving a Pulse Width Modulation (PWM) signal to control speed of the motor. The PWM signal may be provided to the motor controller 202 to control the speed of the electric motor. The speed of the motor may be defined in terms of the RPM and thus, the PWM signal may be used to control the RPM of the motor. The speed of the motor may be controlled by the motor controller 202 using the PWM signal. In an embodiment, the speed of the motor may be controlled by changing the duty cycle of the PWM signal. Thus, the duty cycle of the PWM signal may be adjusted to control the speed of the motor as per requirement. The variation in the speed of the motor may be helpful when the motor gets jammed and additional force is required to get rid of the jam. Such additional force may be provided by increasing the speed of the

motor. In another example, there may be a requirement for extra fuel supply, which may be easily fulfilled by increasing the speed of the motor. Hence, the ability to change the speed of the motor as per the requirement may be very useful and such changes in the speed of the motor may be controlled efficiently using the PWM signal.
[0046] At step 304, the method discloses bypassing, via a voltage surge protection diode 206 coupled between the motor controller and an input terminal of the power supply circuit in parallel connection, excess voltage at an input terminal of the power supply circuit to a ground terminal of the power supply circuit by connecting the input terminal with the ground terminal, when the voltage at the input terminal is greater than a pre-defined upper threshold. In an embodiment, the voltage surge protection diode 206 may be a Zener diode. The upper threshold may be the maximum voltage which may be provided to the motor controller 202 without causing any damage to the motor controller 202 and/or other elements of the circuit 200. The voltage surge protection diode 206 may be coupled between the motor controller 202 and the input terminal 210 in the parallel connection such that a negative terminal of the voltage surge protection diode 206 is coupled with the input terminal 210 and a positive terminal of the voltage surge protection diode 206 is coupled with the ground terminal 212 of the power supply circuit 200. In this manner, the method may provide protection against the voltage surge in the circuit.
[0047] The method 300, at step 306, may further disclose maintaining, via a pair of voltage regulation capacitors coupled between the motor controller and the input terminal of the power supply circuit in a parallel connection, a supply voltage for the motor controller at a fixed value by way of discharging, when the voltage at the input terminal of the power supply circuit is less than a pre-defined lower threshold. The voltage regulation capacitors 208 may maintain a supply voltage for the motor controller 202 at a fixed value by discharging the charge stored therein when the voltage available at the input terminal 201 of the power supply circuit 200 is less than the pre-defined lower threshold. Thus, whenever the supply

voltage drops below the lower threshold, the voltage regulation capacitors 208 may discharge to provide sufficient voltage to the motor controller 202 to operate the motor. In an embodiment, the fixed value of the voltage may be a voltage required by the motor controller 202 to operate the motor. In figure 2, there are two capacitors 208a and 208b are shown as the voltage regulation capacitors 208, but there may be more or less than two capacitors to maintain the supply voltage in case of the voltage undershoot. In an embodiment, the voltage regulation capacitor 208 may be a bulk capacitor, but not limited thereto.
[0048] In an embodiment, the method 300 may further comprise providing protection against electrostatic discharge via an electrostatic discharge protection capacitor 214 coupled between the motor controller 202 and the input terminal 210 of the power supply circuit 200 in the parallel connection. The electrostatic discharge protection capacitor 214 may provide protection against electrostatic discharge in the power supply circuit 200. The method 300 may also comprise providing protection against reverse voltage protection element via a reverse voltage protection unit which may be coupled between the motor controller 202 and the input terminal 212 of the power supply circuit 200 to provide protection against reverse voltage. The reverse voltage protection unit 216 may comprise a transistor Ql, diode Dl, and resistor R as shown in fig. 2. The first terminal of the reverse voltage protection unit 216 may be coupled with the motor controller 202, a second terminal of the reverse voltage protection unit 216 may be coupled with the input terminal 212 of the power supply circuit 200, and a third terminal of the unit 216 may be coupled with the ground. In an embodiment, the diode Dl may be a Zener diode, but not limited thereto.
[0049] In this manner, the method enables the motor to operate at variable RPM with the help of PWM input. In this way, the motor may be self-cleaned by operating at higher RPM for few seconds. Further, the motor controller is also electrically protected for sudden high voltage. Further, the motor controller

remains operational in case of sudden decrease in voltage during start & running state. In this way, the RPM of the motor remains stabilized.
[0050] The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.
[0051] Suitable processors/controllers include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine.

We Claim:

A power supply circuit for a motor controller of a motor, the power supply circuit omprises:
a Pulse Width Modulation (PWM) signal input to receive a PWM signal for the motor ontroller to control speed of the motor;
a voltage surge protection diode, coupled between the motor controller and an input ;rminal of the power supply circuit in parallel connection, to bypass excess voltage at the input ;rminal to a ground terminal of the power supply circuit by connecting the input terminal with le ground terminal, when the voltage at the input terminal is greater than a pre-defined upper ireshold; and
a pair of voltage regulation capacitors, coupled between the motor controller and the input ;rminal of the power supply circuit in the parallel connection, to maintain a supply voltage for le motor controller at a fixed value by way of discharging, when the voltage available at the lput terminal of the power supply circuit is less than a pre-defined lower threshold.
The power supply circuit as claimed in claim 1, wherein the speed of the motor is ontrolled by changing a duty cycle of the PWM signal.
The power supply circuit as claimed in claim 1, wherein a negative terminal of the oltage surge protection diode is coupled with the input terminal of the power supply circuit nd a positive terminal of the voltage surge protection diode is coupled with the ground ;rminal of the power supply circuit.
The power supply circuit as claimed in claim 1, further comprises an electrostatic ischarge protection capacitor, coupled between the motor controller and the input terminal of le power supply circuit in the parallel connection, to provide protection against electrostatic ischarge.
The power supply circuit as claimed in claim 1, further comprises a reverse voltage rotection unit, coupled between the motor controller and the input terminal of the power apply circuit to provide protection against reverse voltage, wherein a first terminal of the averse voltage protection unit is coupled with the motor controller, a second terminal of the averse voltage protection unit is coupled with the input terminal of the power supply circuit,

A method of operating a power supply circuit for a motor controller of a motor, the lethod comprises:
receiving a Pulse Width Modulation (PWM) signal to control speed of the motor;
bypassing, via a voltage surge protection diode coupled between the motor controller and 11 input terminal of the power supply circuit in parallel connection, excess voltage at the input ;rminal of the power supply circuit to a ground terminal of the power supply circuit by onnecting the input terminal with the ground terminal, when the voltage at the input terminal i greater than a pre-defined upper threshold; and
maintaining, via a pair of voltage regulation capacitors coupled between the motor ontroller and the input terminal of the power supply circuit in the parallel connection, a supply oltage for the motor controller at a fixed value by way of discharging, when the voltage at the lput terminal of the power supply circuit is less than a pre-defined lower threshold.
The method as claimed in claim 6, wherein the speed of the motor is controlled by hanging a duty cycle of the PWM signal.
The method as claimed in claim 6, wherein a negative terminal of the voltage surge rotection diode is coupled with the input terminal of the power supply circuit and a positive ;rminal of the voltage surge protection diode is coupled with the ground terminal of the power apply circuit.
The method as claimed in claim 6, further comprises providing protection against lectrostatic discharge via an electrostatic discharge protection capacitor coupled between the lotor controller and the input terminal of the power supply circuit in the parallel connection.
0. The method as claimed in claim 6, further comprises providing protection against averse voltage via a reverse voltage protection unit coupled between the motor controller and le input terminal of the power supply circuit, wherein a first terminal of the reverse voltage rotection unit is coupled with the motor controller, a second terminal of the reverse voltage rotection unit is coupled with the input terminal of the power supply circuit, and a third ;rminal of the reverse voltage protection unit is coupled with the ground terminal.