Pseudo current tracking for power conditioning

Abstract

The present application relates to pseudo current tracking for power regulation. In the described example, a power supply circuit (100) includes a regulation circuit (110) that receives an input voltage (VIN) and provides a regulated output voltage (VOUT) based on the input voltage (VIN). The regulation circuit (110) includes a switching device (120) having a switching output (122) that generates a ripple current waveform in a current regulator (124) to provide the regulated output voltage (VOUT). A control circuit (130) includes a pseudo current tracker (PCT) (134) that is operably coupled to the regulation circuit (110). The PCT (134) receives a reference voltage (VREF) and generates a ripple voltage waveform that is proportional to the ripple current waveform. The control circuit (130) commands the switching device (120) to generate the ripple current waveform based on the ripple voltage waveform such that the regulated output voltage (VOUT) approaches the reference voltage (VREF).

Description

[0001] This application is a divisional application of Chinese Patent Application 201780047507.4, filed August 03, 2017, entitled "Pseudo-Current Tracking for Power Supply Regulation." TECHNICAL FIELD

[0002] The present invention relates generally to circuitry, and more specifically to power supply circuitry and methods that regulate an output voltage based on pseudo-current tracking of a current regulator. BACKGROUND

[0003] Switching DC-to-DC regulators convert a direct current (DC) input voltage to a DC output voltage using various techniques. A buck regulator converts a higher DC input voltage to a lower DC output voltage. A boost regulator performs the opposite function of a buck regulator by providing a higher DC output voltage converted from a lower DC input voltage. An example of a switching converter is a current-mode converter. In this example, a controllable switch drives an inductive element that provides current to an output load based on a switching duty cycle applied to the switch by a controller. The controller can regulate the output voltage by comparing the output voltage to a reference voltage, where the duty cycle of the switch and the current in the inductor can be controlled based on the comparison. SUMMARY

[0004] In described examples, a power supply circuit includes a regulation circuit that receives an input voltage and provides a regulated output voltage based on the input voltage. The regulation circuit includes a switching device having a switched output that generates a ripple current waveform in a current regulator to provide the regulated output voltage. A control circuit includes a pseudo-current tracker (PCT) that is operably coupled to the regulation circuit. The PCT receives a reference voltage and generates a ripple voltage waveform that is proportional to the ripple current waveform. The control circuit commands the switching device to generate the ripple current waveform based on the ripple voltage waveform such that the regulated output voltage approaches the reference voltage, where the ripple voltage waveform is proportional to the ripple current waveform if the regulated output voltage approaches the reference voltage, and the ripple voltage waveform is not proportional to the ripple current waveform if the regulated output voltage is different from the reference voltage.

[0005] In another example, the power supply circuit includes a regulation circuit that receives an input voltage and provides a regulated output voltage based on the input voltage. The regulation circuit includes a switching device with a switching output that drives a current regulator to provide the regulated output voltage in response to a control command. The switching output of the switching device generates a ripple current waveform in the current regulator to provide the regulated output voltage. A control circuit with a pseudo-current tracker (PCT) is operatively coupled to the regulation circuit. The PCT receives a reference voltage and generates a ripple voltage waveform. The output circuit of the control circuit monitors the ripple voltage waveform of the PCT relative to a peak-threshold voltage to generate a control command for the switching device. The PCT generates a ripple voltage waveform proportional to the ripple current waveform. The control circuit commands the switching device to generate a ripple current waveform based on the ripple voltage waveform such that the regulated output voltage approaches the reference voltage, wherein if the regulated output voltage approaches the reference voltage, the ripple voltage waveform is proportional to the ripple current waveform; if the regulated output voltage differs from the reference voltage, the ripple voltage waveform is not proportional to the ripple current waveform.

[0006] In another example, a method includes generating a ripple current waveform in a current regulator to provide a regulated output voltage in response to a control command. The method includes generating a ripple voltage waveform proportional to the ripple current waveform of the current regulator. The method includes controlling the regulated output voltage by commanding a switching device via a control command to generate a ripple current waveform based on the ripple voltage waveform, such that the regulated output voltage approaches a reference voltage, wherein if the regulated output voltage approaches the reference voltage, the ripple voltage waveform and the ripple current waveform are proportional; if the regulated output voltage differs from the reference voltage, the ripple voltage waveform and the ripple current waveform are not proportional. Attached Figure Description

[0007] Figure 1 An example block diagram of a power supply circuit for regulating output voltage based on pseudo-current tracking of a current regulator is provided.

[0008] Figure 2 An example circuit implementation of a power supply circuit that regulates the output voltage based on pseudo-current tracking of a current regulator is described.

[0009] Figure 3 Explanation Figure 2 Example waveforms of the discontinuous conduction mode (DCM) of the circuit.

[0010] Figure 4 Explanation Figure 2 Example waveforms of the continuous conduction mode (CCM) of the circuit.

[0011] Figure 5An example circuit implementation of a power supply circuit regulating an output voltage based on pseudo-current tracking of a current regulator is illustrated, in which output overload protection is provided.

[0012] Figure 6 An example waveform of the circuit of Figure 5

[0013] Figure 7 An alternative example circuit implementation of a power supply circuit regulating an output voltage based on pseudo-current tracking of a current regulator is illustrated.

[0014] Figure 8 An example method of regulating an output voltage based on pseudo-current tracking of a current regulator is illustrated. DETAILED DESCRIPTION

[0015] The present specification relates to power supply circuits and methods regulating an output voltage based on pseudo-current tracking of a current regulator. The power supply circuit includes a regulation circuit and a control circuit to provide switch pulse width modulation (PWM) control for output voltage regulation based on an input voltage. In some examples, the regulator can be a boost regulator, a buck regulator, or a buck / boost regulator. A switching device with a switching output in the regulation circuit drives the current regulator to provide a regulated output voltage in response to a control command. The switching output of the switching device generates a ripple current waveform in the current regulator to provide the regulated output voltage based on on and off times of the switching device in response to the control command. When the switching device is on, the ripple current waveform increases because the input voltage is provided to the current regulator via the switch. When the switching device is off, the ripple current waveform decreases with a given slope that decays over time.

[0016] ​The control circuit includes a pseudo-current tracker (PCT) coupled to the regulation circuit. The pseudo-current tracker is referred to as "pseudo" because it does not directly measure the ripple current waveform in the current regulator, but it simulates the current waveform by generating a ripple voltage (e.g., a sawtooth voltage) that is proportional to the ripple current of the current regulator when the power supply is in regulation. If the output circuit is in regulation, the PCT receives the reference voltage and generates a ripple voltage waveform that proportionally tracks the ripple current waveform of the current regulator. In one example when not in regulation (e.g., the output voltage is less than the reference voltage), the control circuit commands the switching device to turn on if the ripple voltage waveform of the PCT has a slope that rises faster than the slope of the ripple current waveform. In another example when not in regulation (e.g., the output voltage is greater than the reference voltage), the control circuit commands the switching device to turn off if the ripple voltage waveform of the PCT has a slope that rises slower than the slope of the ripple current waveform. If the respective slopes are proportional, indicating that the power supply is in regulation, the period of time that the switching device is on is about the same amount of time that it is off. Overload protection can be provided in the power supply circuit to mitigate short circuit and over current load conditions in the power supply circuit.

[0017] Figure 1 An example of a power supply circuit 100 that regulates an output voltage based on pseudo-current tracking of a current regulator is illustrated. As used herein, the term "circuit" can include a collection of active and / or passive elements that perform a circuit function, such as an analog circuit or a digital circuit. Additionally or alternatively, for example, the term "circuit" can include an integrated circuit (IC) in which all or some of the circuit elements are fabricated on a common substrate, such as a semiconductor substrate, for example, a die or a chip. The term "pseudo" as used herein refers to a signal that is generated to track, replicate, or simulate another signal, without directly measuring or sampling the other signal. For example, the term "pseudo-current tracker" refers to a circuit function that simulates a ripple current waveform by generating another signal that is a ripple voltage waveform. The ripple voltage waveform is not the same signal as the ripple current waveform, but it has many of the same properties (e.g., slope, shape, and peak-to-peak amplitude) that are useful to the regulation circuit. Thus, the ripple voltage waveform as described herein is referred to as a pseudo form of the ripple current waveform. When the power supply circuit described herein is in regulation (e.g., the output voltage is close to the reference voltage), the ripple voltage waveform has substantially the same signal shape (e.g., a sawtooth waveform) by simulating the signal shape of the ripple current waveform.

[0018] The power supply circuit 100 includes a regulation circuit 110 that receives an input voltage VIN 114 and provides a regulated output voltage VOUT 116 based on the input voltage. The regulation circuit 110 includes a switching device 120 having a switching output 122 that drives a current regulator 124 to provide the regulated output voltage VOUT 116. The switching output 122 of the switching device 120 generates a ripple current waveform in the current regulator 124 to provide the regulated output voltage VOUT 116. A control circuit 130 having a pseudo-current tracker (PCT) 134 is operably coupled to the regulation circuit 110 via a coupling network 140. The PCT 134 receives a reference voltage VREF 144 via the coupling network 140 and generates a ripple voltage waveform that is proportional to the ripple current waveform. The control circuit 130 commands the switching device 120 to generate the ripple current waveform based on the ripple voltage waveform so that the regulated output voltage VOUT 116 approaches the reference voltage VREF 144. In one example, the PCT 134 is a capacitive device (e.g., a capacitor, a bank of capacitors) driven from the coupling network 140. The current regulator 110 can include an inductive device (e.g., an inductor, a transformer winding) driven by the switching device 120 to generate the ripple current waveform.

[0019] The PCT 134 indirectly and continuously tracks the ripple current of the current regulator 124, thus not losing track of the output voltage as in some conventional current mode power supplies. With this pseudo-current monitoring approach, the current in the current regulator 124 can be continuously monitored to control VOUT 116 without directly sampling the current in the current regulator, which allows for effective and responsive control of VOUT based on changes in the load current. When VOUT 116 approaches VREF 144, the proportionality between the ripple voltage waveform and the ripple current waveform remains unchanged. If VOUT 116 is different from VREF 144, the proportionality is not maintained until when VOUT again approaches VREF in the regulation state. For example, if the regulated output voltage VOUT 116 is less than the reference voltage VREF 144, the ripple voltage waveform of the PCT 134 has a slope that rises faster than the slope of the ripple current waveform, resulting in the control circuit 130 commanding the switching device 120 to turn on. Conversely, if the regulated output voltage VOUT 116 is greater than the reference voltage VREF 144, the ripple voltage waveform of the PCT 134 has a slope that rises slower than the slope of the ripple current waveform, which results in the control circuit 130 delaying turning on the switching device 120. If the respective slopes are proportional, indicating that the power supply 100 is in the regulation state where VOUT 116 approaches VREF 144, the period of time that the switching device 120 is on is approximately the same amount of time that it is off.

[0020] The control circuit 130 includes an output circuit 150 (where the ripple voltage waveform of the PCT 134 is monitored by the output circuit) to generate a control command for controlling the switching device 120 of the regulation circuit 110. The control command controls the duty cycle of the switching device 120, which defines the on time relative to the off time of the device. The output circuit 150 can include a comparator and a flip-flop (see, e.g., Figure 2 ). The comparator drives the flip-flop to generate the control command for controlling the switching device 120. The comparator monitors the ripple voltage waveform of the PCT 134 relative to the peak threshold voltage 140. The peak threshold voltage 160 controls the peak-to-peak amplitude of the peak ripple voltage waveform of the PCT 134 and the peak-to-peak amplitude of the peak ripple current waveform of the current regulator 110. The output circuit 150 can include another comparator (see, e.g., Figure 2 ) that monitors the ripple voltage waveform relative to ground to generate a reset signal to the flip-flop, which turns off the switching device 120.

[0021] A rectifier REC1 is coupled to the switching output 122 and discharges from the current regulator 110 when the switching device 120 is off. For example, the rectifier REC1 can be a diode or a synchronous rectifier. As shown, a coupling network 140 connects the regulation circuit 110 to the control circuit 130. The coupling network 140 includes a first resistor (see, e.g., Figure 2 ) that couples a node 170 of the rectifier REC1 and a negative node of the regulated output voltage VOUT 116 to the PCT 134. The coupling network 140 also includes a second resistor that couples the reference voltage VREF 144 to the PCT 134, where the negative node of the regulated output voltage drives current through the first resistor when the switching device 120 is on. The first and second resistors of the coupling network 140 can be set to approximately equal resistance values to set the regulated output voltage VREF 116 to approximately equal the reference voltage VREF 144. The first and second resistors of the coupling network 140 can be set to different values for scaling the regulated output voltage different from the reference voltage. An overload comparator (see, e.g., Figure 5 ) can be provided to monitor the node 170 of the rectifier REC1 relative to ground. The overload comparator controls a gate that controls the on time of the switching device 120, where if the node 170 of the rectifier REC1 goes positive, the switching device turns on, which indicates that the ripple current waveform of the current regulator is at approximately zero amps at that time. The regulation circuit 110 and the control circuit 130 can be configured as a buck regulator, a boost regulator, or a buck / boost regulator.

[0022] An overload comparator (see, e.g., Figure 5) to monitor node 170 of diode Dl relative to ground. The overload comparator controls a gate that controls when the switching device 120 turns on. When node 170 of diode Dl goes positive, the switching device 120 turns on, which indicates that the ripple current waveform of current regulator 124 is approximately zero amps at that time. The overload comparator mitigates short circuits and overload currents requested from VOUT 116. For example, the regulation circuit 110 and control circuit 130 can be configured as a buck regulator, a boost regulator, or a buck / boost regulator.

[0023] Figure 2 An example circuit implementation of a power supply circuit 200 that regulates an output voltage based on current regulator-based pseudo-current tracking is illustrated. The circuit 200 includes a regulation circuit 204 having a switching device 210 (e.g., metal oxide field effect transistor, bipolar transistor) that switches an input voltage VIN 214 through a current regulator 216 to generate a regulated output voltage VOUT 220. The current regulator 216 includes an inductor LI modeled with a series resistance (shown as R_L1) to drive load components COUT1 and RLOAD1. A diode Dl is driven by the switching device 210 and coupled to LI at a switching output 224, which represents a ground node common to a ground connection of a control circuit 230. A coupling network including Rl and R2 couples a reference voltage VREF 234 and a node 240 of the regulation circuit 204 to a pseudo-current tracker (PCT) (shown as a capacitor CI at node 244). An output circuit 250 monitors node 244 of the PCT capacitor CI relative to a peak threshold voltage 254 via comparators Al and A2. Outputs from Al and A2 drive a flip-flop 260 to generate a control command to the switching device 210.

[0024] If VREF 234 is approximately equal to the desired output voltage VOUT 220, the switch device 210 is on, where the PCT capacitor CI discharges with a current proportional to the difference between the input and output voltages (Vin / Rl - Vout / R2) until the voltage at node 244 reaches ground and the comparator A2 resets the flip-flop 260, causing the switch device 210 to turn off. If the peak voltage threshold 254 is << VOUT 220, the PCT capacitor CI can now charge with a current proportional to the desired output voltage (VREF / R2) until the voltage at node 244 reaches the threshold 254 and the comparator Al sets the flip-flop 260, turning on the switch device 210 and repeating the cycle. Thus, the circuit 200 can oscillate between on and off states to maintain the current in the inductor LI with a peak-to-peak ripple proportional to the peak-to-peak voltage on the PCT capacitor CI (approximately equal to the peak threshold voltage 254). The circuit 200 can regulate the output voltage VOUT 220 of the converter to a value slightly below the reference voltage VREF 234, where VOUT is close to VREF.

[0025] If the load RLOAD1 increases and causes the output voltage VOUT 220 to drop below VREF 234, the up slope of the voltage on the PCT capacitor CI should be faster than the up slope of the inductor current of LI, so the switch device 210 should turn on. Thus, the average current of the inductor LI should increase, causing the output voltage VOUT 220 to increase until it becomes approximately equal to VREF 234 and the circuit 200 reaches a steady state where the output voltage is regulated to the voltage of VREF. If the load RLOAD1 decreases, the output voltage VOUT 220 should increase and track closer to the value of VREF 234. Thus, the current in the inductor LI should reach a minimum before the voltage on the PCT capacitor CI reaches the peak threshold voltage 254, where the diode DI stops conducting and the current charging the capacitor CI should drop to a low value, delaying the setting of the flip-flop 260 and turning on the switch device 210. Thus, the average current in the inductor LI should decrease to a value to maintain a small difference between VOUT 220 and VREF 234.

[0026] Figure 3 An example waveform representing the discontinuous conduction mode (DCM) of the circuit of Figure 2 is illustrated. As used herein, the term discontinuous mode refers to the period of time that the inductor current described herein remains at a steady state value and the ripple voltage described herein remains fixed at some fixed DC value for the same period of time. Figure 3Including inductor waveform 310, which shows the inductor current on the vertical axis relative to time on the horizontal axis. Waveform 320 shows the PCT ripple voltage waveform simulating the inductor current waveform 310. Figure 330 shows... Figure 2 The regulator is in regulation mode, where the output voltage VOUT at 334 remains slightly lower than the reference voltage shown at 336. Figure 340 shows the... Figure 2 The switching device 210 is switched on by signal 344, where the inductor current reaches its peak and the PCT voltage of 320 is reset to approximately zero. Although the waveforms of 310 and 320 are inverted relative to each other, the waveform 320, representing the ripple voltage, substantially tracks and simulates the waveform 310, representing the inductor current (e.g., waveforms 310 and 320 are substantially proportional to each other). The discontinuous period of the inductor current is shown at 350.

[0027] Figure 4 Explanation Figure 2 Example waveforms of the continuous conduction mode (CCM) of the circuit. As used herein, the term continuous mode refers to the inductor current described herein changing and not reaching a state similar to... Figure 3 The time period of the steady-state values ​​of the described discontinuous mode. Similar to... Figure 3 , Figure 4 Including inductor waveform 410, which shows the inductor current on the vertical axis relative to time on the horizontal axis. Waveform 420 shows the PCT ripple voltage waveform simulating the inductor current waveform 410. Figure 430 shows... Figure 2 The regulator is in regulation mode, where the output voltage VOUT at 434 remains slightly lower than the reference voltage shown at 436. Figure 440 shows the... Figure 2 The switching device 210 receives a switch-on signal 444, during which the inductor current reaches its peak and the PCT voltage of 420 is reset to approximately zero. Although the waveforms of 410 and 420 are inverted relative to each other, the waveform 420, representing the ripple voltage, substantially tracks and simulates the waveform 410, representing the inductor current (e.g., waveforms 410 and 420 are substantially proportional to each other). As shown, the inductor current of 410 continuously switches between a certain maximum and minimum current value, but does not reach a steady-state value. As shown, the ripple voltage waveform 420 substantially tracks waveform 410.

[0028] Figure 5 This describes an example circuit implementation of a power supply circuit 500 that regulates the output voltage based on pseudo-current tracking of a current regulator, wherein output overload protection is provided. Circuit 500 includes a regulating circuit 510 with a switching device 520, which is controlled via a control circuit 530. Circuits 500 and 200 (combined above) Figure 2There is a similarity between the circuits described in the Background section, and therefore each component of the circuit 500 will not be described herein. As shown, the control circuit 530 includes comparators Al and A2 to generate set and reset command signals to flip-flop 540 to set and reset the switching device 520, respectively. However, in this example, an overload comparator A3 is provided to monitor the node of diode Dl with respect to ground 550. Comparator A3 controls gate Gl (e.g., an AND gate) which controls when the switching device 520 is turned on. When the node 550 of diode Dl goes positive, the switching device 520 is turned on, which indicates that the ripple current waveform of the current regulator described herein at that time is approximately zero amps.

[0029] Because the peak-to-peak inductor current ripple can be set without the need to directly sense the inductor current, the converter 500 can be protected from overloads and short circuits by forcing the operating mode of the converter in an overload condition. For example, continuous conduction mode (CCM) operation can be forced by allowing the switching device 520 to turn on after the inductor current has dropped to zero. This can be accomplished by sensing the voltage at node 550 (which is negative (equal to the forward drop of diode Dl) as long as the inductor is carrying current) and then allowing the switching device 520 to turn on after the node 550 goes positive (e.g., the inductor current has dropped to approximately zero).

[0030] Figure 6 An example waveform of the circuit of Figure 5 is illustrated. During the initial start-up of the converter, the waveform graph 600 shows the output voltage increasing during time period Tl. Also during this time Tl, the inductor current is shown in graph 610. At time period T2, the output voltage of graph 600 reaches steady state, with the corresponding inductor current graph 610 operating in discontinuous mode as described above. At time period T3, the output voltage VOUT is shorted in graph 600, with the inductor current being switched to continuous conduction mode (CCM) in graph 610 by the overload circuit described in the Background section. Figure 5

[0031] Figure 7 ​An alternative circuit implementation of power supply circuit 700 is illustrated that regulates output voltage based on pseudo-current tracking of a current regulator. In this example, a boost or fly-back circuit is illustrated. Similar to the power supply circuits described above, an output from control flip-flop 710 drives switching device 720, which in turn drives series inductors LM and LI connected across the primary of fly-back transformer Tl. An output from the secondary of Tl drives one side of a coupled network with balanced 1 mega-ohm resistors. The other side of the coupled network is driven from VREF as shown at 730. A pseudo-current tracker CI is provided to generate a ripple voltage waveform that is proportional to the ripple current waveform of LI in the primary of Tl. Similar to the circuits described above, the output voltage is regulated by simulating the inductor current of LI with the ripple voltage waveform generated by PCT capacitor CI, which is fed to the inputs of comparators Al and A2 to control flip-flop 710.

[0032] In view of the structural and functional features described above, reference is made to Figure 8 An example method is described. For simplicity of illustration, the method is shown and described as being performed serially, but the method is not limited by the order shown since portions of the method can occur in different orders and / or concurrently than shown and described herein. Such a method can be implemented by various hardware circuits and other components configured to perform the functions shown and described.

[0033] Figure 8 An example method 800 is described that regulates output voltage based on pseudo-current tracking of a current regulator. At 810, method 800 includes generating a ripple current waveform in the current regulator in response to a control command (e.g., via Figure 1 switching device 120 and current regulator 124) to provide a regulated output voltage. If the regulated output voltage is close to a reference voltage, the ripple voltage waveform is proportional to the ripple current waveform, and if the regulated output voltage is different from the reference voltage, the ripple voltage waveform is not proportional to the ripple current waveform. At 820, method 800 includes generating a ripple voltage waveform that is proportional to the ripple current waveform of the current regulator (e.g., via Figure 1 pseudo-current tracker 134). At 830, method 800 includes controlling the regulated output voltage by commanding the switching device via the control command to generate the ripple current waveform based on the ripple voltage waveform such that the regulated output voltage is close to the reference voltage (e.g., via Figure 1the control circuit 130 of the PCT). Although not shown, the method 800 can also include commanding the switching device to turn on if the ripple voltage waveform of the PCT has a slope that rises faster than the slope of the ripple current waveform, and commanding the switching device to turn off if the ripple voltage waveform of the PCT has a slope that rises slower than the slope of the ripple current waveform.

[0034] As used herein, the term "based on" means based at least in part on. Also, in the description herein, any reference to language, for example, "an" or "a", "first" or "second", etc., means that a particular element or item is either present or not present but not both. Thus, these terms, when they refer to a particular claim, mean either that claim or none.

[0035] In the described embodiments, modifications are possible and other embodiments are possible within the scope of the claims.

Claims

1. A power supply circuit comprising: a regulation circuit configured to receive an input voltage at a voltage input and provide a regulated output voltage at a voltage output, the regulation circuit comprising: a switching device having a switching output; and a current regulator coupled to the switching output and configured to generate a ripple current waveform based on a signal received at the switching output to provide the regulated output voltage; and a control circuit comprising: a current tracker coupled to the regulation circuit and configured to receive a reference voltage and generate a ripple voltage waveform having a rising slope based on the ripple current waveform and a difference between the regulated output voltage and the reference voltage, wherein the control circuit is configured to control the switching device to generate the ripple current waveform based on the ripple voltage waveform to regulate the regulated output voltage.

2. The power supply circuit of claim 1, wherein, if the regulated output voltage is less than the reference voltage, the slope of the ripple voltage waveform rises faster than the slope of the ripple current waveform, causing the control circuit to command the switching device to turn on.

3. The power supply circuit of claim 1, wherein, if the regulated output voltage is greater than the reference voltage, the slope of the ripple voltage waveform rises slower than the slope of the ripple current waveform, which causes the control circuit to delay turning on the switching device.

4. The power supply circuit of claim 1, wherein the current tracker comprises a capacitor coupled to the regulation circuit, and the control circuit further comprises an output circuit, wherein the ripple voltage waveform is monitored by the output circuit to generate a control command to control the switching device of the regulation circuit, the control command controlling a duty cycle of the switching device, the duty cycle defining an on time relative to an off time of the switching device.

5. The power supply circuit of claim 4, wherein the output circuit comprises a comparator and a flip-flop, wherein the comparator is configured to drive the flip-flop to generate the control command to control the switching device, and the comparator is configured to monitor the ripple voltage waveform relative to a peak threshold voltage, the peak threshold voltage configured to control a peak-to-peak amplitude of the peak ripple voltage waveform of the current tracker and a peak-to-peak amplitude of the peak ripple current waveform of the current regulator.

6. The power supply circuit of claim 5, wherein the output circuit comprises another comparator monitoring the ripple voltage waveform relative to ground to generate a reset signal to the flip-flop to turn off the switching device.

7. The power supply circuit of claim 1, wherein the voltage output comprises a positive terminal and a negative terminal, the power supply circuit further comprising a rectifier having a first terminal coupled to the switching output and a second terminal coupled to the negative terminal of the voltage output, wherein the rectifier is configured to discharge from the current regulator when the switching device is off.

8. The power supply circuit of claim 7, further comprising a coupling network coupled between the regulation circuit and the control circuit, the coupling network including a first resistor coupled between the negative terminal of the voltage output and the current tracker, the coupling network including a second resistor coupled between the reference voltage and the current tracker, wherein the negative terminal of the voltage output is configured to drive a current through the first resistor when the switching device is on.

9. The power supply circuit of claim 8, wherein the first and second resistors of the coupling network are substantially equal in resistance value to set the regulated output voltage to be substantially equal to the reference voltage, the first and second resistors of the coupling network are set to different values to scale the regulated output voltage to be different than the reference voltage.

10. The power supply circuit of claim 8, further comprising an overload comparator coupled to the switching device, and the overload comparator is configured to monitor the second terminal of the rectifier with respect to ground, wherein the overload comparator is configured to turn on the switching device when the second terminal of the rectifier goes positive, which indicates that the ripple current waveform of the current regulator is substantially zero amperes at that time.

11. The power supply circuit of claim 1, wherein the regulation circuit and the control circuit are configured as a buck regulator, a boost regulator, or a buck / boost regulator.

12. A power supply circuit comprising: a regulation circuit configured to receive an input voltage at a voltage input and provide a regulated output voltage at a voltage output, the regulation circuit comprising: a switching device having a switching output; and a current regulator coupled to the switching output and configured to generate a ripple current waveform to provide the regulated output voltage in response to a control command based on a signal received at the switching output; and a control circuit having: a current tracker coupled to the regulation circuit and configured to receive a reference voltage and generate a ripple voltage waveform; and an output circuit of the control circuit configured to monitor the ripple voltage waveform of the current tracker with respect to a peak threshold voltage to generate the control command to the switching device, wherein the current tracker is configured to generate the ripple voltage waveform with a rising slope based on the ripple current waveform and a difference between the regulated output voltage and the reference voltage, the control circuit is configured to command the switching device to generate the ripple current waveform based on the ripple voltage waveform to regulate the regulated output voltage.

13. The power supply circuit of claim 12, wherein the output circuit includes a comparator and a flip-flop, wherein the comparator is configured to drive the flip-flop to generate the control command for controlling the switching device, and the comparator is configured to monitor the ripple voltage waveform of the current tracker with respect to a peak threshold voltage, wherein the peak threshold voltage is configured to control a peak-to-peak amplitude of the peak ripple voltage waveform of the current tracker and a peak-to-peak amplitude of the peak ripple current waveform of the current regulator.

14. The power supply circuit of claim 13, wherein the output circuit includes another comparator configured to monitor the ripple voltage waveform with respect to ground to generate a reset signal to the flip-flop, the reset signal configured to turn off the switching device.

15. The power supply circuit of claim 12, further comprising a rectifier having a first terminal coupled to the switching output and a second terminal coupled to a negative terminal of the voltage output, wherein the rectifier is configured to discharge from the current regulator when the switching device is turned off.

16. The power supply circuit of claim 15, wherein the current tracker includes a capacitor coupled to the regulation circuit, the power supply circuit further comprising a coupling network coupled between the regulation circuit and the control circuit, the coupling network including a first resistor coupled between the negative terminal of the voltage output and the current tracker, the coupling network including a second resistor coupled between the reference voltage and the current tracker, wherein the negative terminal of the regulated output voltage is configured to drive a current through the first resistor when the switching device is turned on.

17. The power supply circuit of claim 16, wherein the first and second resistors of the coupling network are substantially equal in resistance value to set the regulated output voltage substantially equal to the reference voltage, the first and second resistors of the coupling network are set to different values to scale the regulated output voltage different from the reference voltage.

18. The power supply circuit of claim 15, further comprising an overload comparator coupled to the switching device, and the overload comparator is configured to monitor the second terminal of the rectifier with respect to ground, the overload comparator configured to turn on the switching device when the second terminal of the rectifier goes positive, which indicates that the ripple current waveform of the current regulator is at a substantially minimum current value at that time.

19. A method of regulating an output voltage, comprising: generating a ripple current waveform to provide a regulated output voltage in response to a control command; generating a ripple voltage waveform proportional to the ripple current waveform; and ​ The regulated output voltage is controlled by commanding the switching device via the control command to generate the ripple current waveform having a slope rise based on the ripple voltage waveform and a difference between the regulated output voltage and a reference voltage to regulate the regulated output voltage.

20. The method of claim 19, further comprising: commanding the switching device to turn on if the ripple voltage waveform has a slope that rises faster than the slope of the ripple current waveform; and commanding the switching device to turn off if the ripple voltage waveform has a slope that rises slower than the slope of the ripple current waveform.

21. A power supply circuit, comprising: a regulation circuit having an input terminal, a first output terminal and a second output terminal, a switch coupled to a ground terminal, an inductor coupled to the switch, and a rectifier coupled between the ground terminal and the second output terminal; and a control circuit having a reference voltage source coupled to the ground terminal, a current tracker coupled to the ground terminal, a first resistor coupled between the second output terminal and the current tracker, a second resistor coupled between the reference voltage source and the current tracker, and an output circuit coupled between the current tracker and a gate of the switch, the current tracker configured to generate a signal based on a difference between a voltage at the second output terminal and the reference voltage source.

22. The power supply circuit of claim 21, wherein the current tracker has a capacitor including a first plate coupled to the ground terminal and a second plate coupled to the first resistor and the second resistor.

23. The power supply circuit of claim 21, wherein the rectifier includes a diode having an anode coupled to the second output terminal and a cathode coupled to the ground terminal.

24. The power supply circuit of claim 21, wherein the output circuit comprises: a first comparator having a first non-inverting input coupled to the current tracker, a first inverting input coupled to a peak voltage source, and a first comparator output; and a second comparator having a second non-inverting input coupled to the ground terminal, a second inverting input coupled to the current tracker, and a second comparator output.

25. The power supply circuit of claim 24, wherein the output circuit comprises a flip-flop having a set input coupled to the first comparator output, a reset input coupled to the second comparator output, and a non-inverting output coupled to the gate of the switch.

26. The power supply circuit of claim 24, wherein the output circuit comprises: a third comparator having a third non-inverting input coupled to the ground terminal, a third inverting input coupled to the second output terminal, and a third comparator output; an AND gate having a first input coupled to the first comparator output, a second input coupled to the third comparator output, and a logic output; and a NAND gate having a first input coupled to the second comparator output, a second input coupled to the third comparator output, and a logic output. a flip-flop having a set input coupled to the logic output, a reset input coupled to the second comparator output, and a non-inverted output coupled to the gate of the switch.

27. The power supply circuit of claim 21, wherein the first resistor has a first resistance and the second resistor has a second resistance equal to the first resistance.

28. The power supply circuit of claim 21, wherein the first resistor has a first resistance and the second resistor has a second resistance different from the first resistance.

29. The power supply circuit of claim 21, wherein the current tracker comprises a capacitor having a first plate coupled to the ground terminal and a second plate coupled to the first resistor and the second resistor; and a diode having an anode coupled to the ground terminal and a cathode coupled to the first resistor and the second resistor.

30. The power supply circuit of claim 21, wherein the regulation circuit comprises a transformer having a primary side coupled to the inductor and a secondary side coupled to the first output terminal and the second output terminal.

31. The power supply circuit of claim 21, wherein the inductor is coupled between the switch and the input terminal.

32. A power supply circuit comprising: a regulation circuit having an input terminal, a ground terminal, and an output terminal, the regulation circuit comprising a switch coupled to the ground terminal, an inductor coupled to the output terminal, and a diode coupled to the ground terminal and the inductor; and a control circuit having: a capacitor comprising a first plate coupled to the ground terminal, and a second plate; a reference voltage source coupled to the ground terminal; a first resistor coupled between the diode and the second plate of the capacitor; a second resistor coupled between the reference voltage source and the second plate of the capacitor; and an output circuit coupled between the second plate of the capacitor and a gate of the switch.

33. The power supply circuit of claim 32, wherein the diode comprises an anode coupled to the first resistor and a cathode coupled to the ground terminal.

34. The power supply circuit of claim 32, wherein the diode comprises an anode coupled to the ground terminal and a cathode coupled to the first resistor.

35. The power supply circuit of claim 32, wherein the output circuit comprises: a first comparator having a first non-inverted input coupled to the second plate of the capacitor, a first inverted input coupled to a peak voltage source, and a first comparator output; and a second comparator having a second non-inverted input coupled to the ground terminal, a second inverted input coupled to the second plate of the capacitor, and a second comparator output.

36. The power supply circuit of claim 35, wherein the output circuit comprises a flip-flop having a set input coupled to the first comparator output, a reset input coupled to the second comparator output, and a non-inverted output coupled to the gate of the switch.

37. The power supply circuit of claim 35, wherein the output circuit comprises: a third comparator having a third non-inverted input coupled to the ground terminal, a third inverted input coupled to the output terminal, and a third comparator output; an AND gate having a first input coupled to the first comparator output, a second input coupled to the third comparator output, and a logic output; and a flip-flop having a set input coupled to the logic output, a reset input coupled to the second comparator output, and a non-inverted output coupled to the gate of the switch.

38. The power supply circuit of claim 32, wherein the first resistor has a first resistance and the second resistor has a second resistance equal to the first resistance.

39. The power supply circuit of claim 32, wherein the first resistor has a first resistance and the second resistor has a second resistance different from the first resistance.

40. The power supply circuit of claim 32, wherein the regulation circuit comprises a transformer having a primary side coupled to the inductor and a secondary side coupled to the output terminal. ​

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