TWI555317B - Power converter and slope detection controller and method thereof - Google Patents

Description

Power converter and its slope detection controller and method

The present invention relates to a power converter, and more particularly to a power converter and its slope detection controller and method.

FIG. 1 is a circuit diagram of a conventional DC-to-DC converter. As shown in FIG. 1, the DC-to-DC converter 100 is configured to convert the input voltage Vin to an output voltage Vout via the output stage 110. The DC-to-DC converter 100 is then fed back to the pulse width modulation control unit 120 according to the change of the output voltage Vout to control the operation of the output stage 110 so that the output voltage Vout can be adjusted to a rated output voltage.

FIG. 2 is a schematic diagram showing the waveform of a conventional DC-DC converter at the moment of load change. Referring to FIG. 1 and FIG. 2 together, in the normal operation of the DC-DC converter 100, as shown in the T1 interval of FIG. 2, the DC-DC converter 100 maintains its output voltage Vout at a predetermined range of the rated output voltage. Inside. When the load is converted from a heavy load to a light load, the DC-to-DC conversion is in the T2 interval of Figure 2 because the circuit loop reaction speed in the DC-to-DC converter 100 cannot keep up with the load transient. The inductor current IL provided by the device 100 is still more than the required load current Iload, so the above excess inductor current IL will charge the output capacitor Cout, so that the output voltage Vout rises and the output voltage Vout exceeds the rated output voltage. Set the range, this phenomenon is called overshoot. However, the above situation is unpleasant for product applications.

In view of this, the present invention provides a power converter and its slope detection control The device and method power converter are used to solve the problems described in the prior art.

The invention provides a slope detection controller for a power converter, which comprises a slope detecting unit and an output control unit. The slope detecting unit receives the output voltage of the power converter, and generates a slope detecting signal according to the output voltage. The output control unit is coupled to the slope detecting unit, and provides a control signal according to the slope detecting signal to control the power converter.

In an embodiment of the invention, when the slope detection signal exceeds a preset value, the output control unit generates a control signal.

In an embodiment of the invention, the control signal is used to turn off the first switch of the power converter.

In an embodiment of the invention, the control signal is used to turn off the on-time signal of the time signal generator of the power converter.

In an embodiment of the invention, the control signal is used to turn off the pulse width modulation signal of the power converter.

The invention provides a power converter comprising an output stage, a pulse width modulation control unit and a slope detection controller. The above output stage includes a first changeover switch. The pulse width modulation control unit is coupled to the output stage and controls the operation of the first switching switch of the output stage. The slope detection controller is coupled to the pulse width modulation control unit, and generates a slope detection signal according to the output voltage of the power converter to generate a control signal according to the slope detection signal, so that the pulse width modulation control unit controls The first switch is turned off.

In an embodiment of the invention, the output stage further includes a second switch, which may be referred to as an upper switch, and the second switch may also be referred to as a lower switch.

In an embodiment of the invention, the pulse width modulation control unit includes a driver, and the slope detection controller is coupled to the driver such that the control signal control driver turns off the first switch.

In an embodiment of the present invention, the pulse width modulation control unit includes a time signal generator, and the slope detection controller is coupled to the time signal generator, so that the control signal control time signal generator stops providing the on time signal to close The first switch.

In an embodiment of the invention, the pulse width modulation control unit includes a pulse width modulation generator, and the slope detection controller is coupled to the pulse width modulation generator to enable control The signal control pulse width modulation generator stops providing the pulse width modulation signal to turn off the first switch.

In an embodiment of the invention, the pulse width modulation generator includes an error The amplifier and the first comparator, the slope detection controller is coupled between the error amplifier and the first comparator to utilize the control signal to affect the error signal of the error amplifier, so that the pulse width modulation generator stops providing the pulse width Modulation signal.

In an embodiment of the invention, the pulse width modulation generator includes an error The amplifier, the first comparator and the ramp signal generator, the first input end of the first comparator is coupled to the error amplifier, the second input end of the first comparator is coupled to the ramp signal generator, and the slope detection controller is coupled The ramp signal generator is connected to use the control signal to influence the ramp signal of the ramp signal generator to cause the pulse width modulation generator to stop providing the pulse width modulation signal.

In an embodiment of the invention, the slope detection controller includes slope detection The unit and the output control unit, the slope detecting unit is a differential circuit to provide a slope detecting signal, and the output control unit generates a control signal according to the slope detecting signal.

The invention provides a slope detection control method for a power converter, which package Included: receiving the output voltage of the power converter; providing a slope detection signal according to the output voltage; and generating a control signal according to the slope detection signal to control the power converter.

In summary, the power converter and the slope detection control provided by the present invention The detection control method of the device uses the detection output voltage slope and the open loop control method to suppress the output voltage overshoot phenomenon to improve the system stability.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

100, 300‧‧‧ power converter

110, 31‧‧‧ Output stage

120, 32‧‧‧ Pulse width modulation control unit

33‧‧‧Slope Detection Controller

121, 321‧‧‧ error amplifier

122, 322‧‧‧ first comparator

123, 323‧‧‧ time signal generator

124, 324‧‧‧ drive

325‧‧‧ Pulse width modulation generator

326‧‧‧ ramp signal generator

329‧‧‧Compensation unit

41‧‧‧Slope detection unit

42‧‧‧Output control unit

Cout‧‧‧ output capacitor

Ctrl‧‧‧ control signal

ERR‧‧‧ error signal

ESR‧‧‧ equivalent series resistance

IL‧‧‧Inductor Current

Iload‧‧‧ load current

Vin‧‧‧Input voltage

Vout‧‧‧ output voltage

V+‧‧‧ positive voltage

UG‧‧‧first switch signal

LG‧‧‧Second switch signal

PHASE‧‧‧ phase node

Pwm‧‧‧ pulse width modulation signal

REF‧‧‧ reference signal

Ramp‧‧‧ ramp signal

SD‧‧‧Slope detection signal

STL‧‧‧Preset

TON‧‧‧ on time signal

SW2‧‧‧Second switch

SW1‧‧‧ first switch

R‧‧‧resistance

C‧‧‧ capacitor

Inv‧‧‧Inverter

Nand‧‧‧

DFF‧‧‧D trigger

S905~S920‧‧‧ Process steps

FIG. 1 is a circuit diagram of a conventional DC-to-DC converter.

FIG. 2 is a schematic diagram showing the waveform of a conventional DC-DC converter at the moment of load change.

3 is a circuit diagram of a power converter in accordance with an embodiment of the present invention.

4 is a circuit diagram of a slope detection controller according to an embodiment of the invention.

FIG. 5 illustrates the transient response of the load after the addition of the slope detection controller is converted from a heavy load to a light load.

6A is a circuit diagram showing a first embodiment of a control mode of a slope detection controller according to the present invention.

6B is a schematic diagram of a driver circuit of a first embodiment of a control mode of a slope detection controller according to the present invention.

7A is a circuit diagram showing a second embodiment of a control method of a slope detection controller according to the present invention.

7B is a schematic diagram of a time signal generator circuit of a second embodiment of a control method of a slope detection controller according to the present invention.

FIG. 8A is a circuit diagram showing a third embodiment of a control mode of a slope detecting controller according to the present invention.

8B is a schematic diagram of a control error signal circuit of a third embodiment of a control method of a slope detection controller according to the present invention.

8C is a schematic diagram of a control ramp signal circuit of a third embodiment of a control method of a slope detection controller according to the present invention.

FIG. 9 illustrates a slope detection control method of a power converter according to an embodiment of the present invention.

Reference will now be made in detail to the exemplary embodiments embodiments In addition, the same or similar elements or components are used in the drawings and the embodiments to represent the same or similar parts.

In the embodiments described below, when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intervening elements. The term "circuitry" can be used to mean at least one element or elements, or elements that are actively and/or passively coupled together to provide suitable functionality. The term "signal" can mean At least one current, voltage, load, temperature, data, or other signal. The ramp signal can also be a ramp-like signal, a triangular wave signal or a sawtooth wave signal, which can be a ramp-wave in a repeat-descent form or a ramp-wave in a repeat-rise form, depending on the application.

A preferred embodiment of the invention is a power converter. herein In the embodiment, the power converter proposed by the present invention is applied to a power integrated circuit (Power IC), but is not limited thereto.

Please refer to FIG. 3, which illustrates a power conversion according to an embodiment of the present invention. Circuit diagram of the device. As shown in FIG. 3, the power converter 300 includes an output stage 31, a pulse width modulation control unit 32, and a slope detection controller 33. In this embodiment, the pulse width modulation control unit 32 further includes an error amplifier 321, a first comparator 322, a time signal generator 323, and a driver 324. The output stage 31 further includes a first switch SW1 and a second switch. SW2; the first switch SW1 may also be referred to as an upper bridge switch, and the second switch SW2 may also be referred to as a lower bridge switch. In other embodiments, the output stage 31 may also include only one switch, and is not limited to the components such as a diode or an inductor.

The first switch SW1 in the output stage 31 is coupled to the input voltage Vin and the driver 324. The second switch SW2 in the output stage 31 is coupled to the driver 324 and the ground. There is also a phase node PHASE between the first switch SW1 and the second switch SW2, and the phase node PHASE is coupled to one end of the output inductor. In this embodiment, the phase node PHASE is also coupled to the driver 324. In other embodiments, the phase node PHASE may not be coupled to the driver 324, and is not limited thereto.

The error amplifier 321 of the pulse width modulation control unit 32 is coupled to the other end of the output inductor. In other embodiments, the error amplifier 321 can also be coupled to the other end of the output inductor through a voltage dividing unit. In addition, the error amplifier 321 is also coupled to a reference voltage REF, and the magnitude of the reference voltage REF can be related to the rated output voltage of the power converter 300. In this embodiment, the error amplifier 321 provides a voltage type error signal ERR. In other embodiments, the error amplifier 321 can also be replaced by a transduction amplifier (GM) to provide a current type error signal ERR. Limited.

An input end of the first comparator 322 is coupled to the output end of the error amplifier 321 . In this embodiment, the output of the error amplifier 321 is also supplemented by the compensation unit 329 . It is provided to the first comparator 322 after the processing. The other input of the first comparator 322 is configured to receive the ramp signal ramp. The first comparator 322 provides a trigger signal according to the comparison result. The time signal generator 323 is coupled to the first comparator 322 and the driver 324, respectively. The time signal generator 323 provides the on-time signal TON to the driver 324 according to the above-mentioned trigger signal, thereby controlling the operation of the output stage 31. With the coupling of the above components/circuits, the pulse width modulation control unit 32 can be coupled to the output stage 31 and control the operation of the output stage 31.

In an embodiment of the invention, the slope detection controller 33 is coupled to the pulse width The degree modulation control unit 32 controls the pulse width modulation control unit 32 according to the slope of the output voltage Vout of the power converter 300 to further control the operation of the at least one switch of the output stage 31.

4 is a circuit diagram of a slope detection controller according to an embodiment of the present invention schematic diagram. For the description, please refer to FIG. 3 and FIG. 4 together. The slope detection controller 33 includes a slope detecting unit 41 and an output control unit 42. The slope detecting unit 41 is coupled to the output end of the power converter 300 and the output control unit 42 to receive the output voltage Vout of the power converter 300, and generate the slope detecting signal SD according to the slope of the output voltage Vout. In the present embodiment, the slope detecting unit 41 is a differentiating circuit. In other embodiments, the slope detecting unit 41 can also be replaced by other circuits that can detect the slope, and is not limited thereto.

The output control unit 42 is a comparator, and an input terminal receives the slope detection. The signal input SD receives a reference signal having a preset trigger level. When the slope detection signal exceeds the preset value, the output control unit 42 generates a control signal ctrl to control the power converter 300. .

As shown in Figure 5, in the T2 interval, when load transients (load transient) The output control unit 42 can generate the control signal ctrl by detecting the slope of the output voltage Vout to control the first switch SW1 of the output stage 31, so that the inductor current IL no longer charges the output capacitor Cout to solve the output. Voltage Vout overshoot problem. In Fig. 5, the broken line portion is the original response of the conventional DC-to-DC converter, and the solid line is the improved circuit response of this embodiment.

In the present invention, the control signal ctrl provided by the slope detecting controller 33 can be supplied to each component in the pulse width modulation control unit 32 to transmit the control signal. The ctrl affects the operation of the pulse width modulation control unit 32, thereby turning off the first changeover switch SW1 of the output stage 31 so that the output voltage Vout does not continue to rise.

6A to 8C illustrate respective control modes of the slope detecting controller of the present invention. A schematic circuit diagram of one embodiment. 6A is a circuit diagram showing a first embodiment of a control mode of a slope detection controller according to the present invention. In FIG. 6A, the slope detection controller 33 is coupled to the driver 324 of the pulse width modulation control unit 32 for providing the control signal ctrl to the driver 324, so that the driver 324 outputs the first switching switch signal UG to the first switching. The switch SW1 is forcibly turning off the first changeover switch SW1, causing the inductor current IL to stop charging the output capacitor Cout.

6B illustrates a control method of a slope detection controller according to the present invention. A schematic diagram of a driver circuit of an embodiment. In FIG. 6B, when the control signal ctrl is, for example, a high level, the driver 324 outputs the first switching switch signal UG to the first switching switch of the output stage 31 regardless of whether the time signal TON of the time signal generator 323 is turned on or off. SW1 to close the first changeover switch SW1. That is, the priority of the control signal ctrl is greater than the on-time signal TON.

7A illustrates a control method of a slope detection controller according to the present invention. A schematic diagram of the circuit of the second embodiment. In FIG. 7A, the slope detection controller 33 is coupled to the time signal generator 323 for providing the control signal ctrl control time signal generator 323 to cause the time signal generator 323 to stop providing the on-time signal (TON) to the driver 324. And, in turn, the first switch SW1 is forcibly turned off, so that the inductor current IL stops charging the output capacitor Cout.

7B illustrates a control method of a slope detection controller according to the present invention. A schematic circuit diagram of a time signal generator of the second embodiment. In FIG. 7B, when the first comparator 322 provides the trigger signal to the time signal generator 323, the time signal generator 323 provides a constant on-time signal TON (or constant off-time signal) to the driver 324 according to the trigger signal. To control the operation of the output stage 31. However, when the slope detection controller 33 provides the control signal ctrl to the time signal generator 323, the time signal generator 323 will stop providing the on-time signal TON to the driver 324 according to its internal line logic. That is to say, the control signal ctrl provided by the slope detection controller 33 can forcibly turn off the on-time signal TON. produce. That is, the control signal ctrl has the highest priority.

FIG. 8A illustrates a control method of a slope detection controller according to the present invention. A schematic circuit diagram of a three embodiment. In FIG. 8A, the pulse width modulation control unit 32 further includes a pulse width modulation generator 325. The slope detection controller 33 is coupled to the pulse width modulation generator 325 of the pulse width modulation control unit 32 to provide the control signal ctrl to control the pulse width modulation generator 325 to stop providing the pulse width modulation signal pwm to The driver 324 is forcibly cut-off the ongoing conduction period (Ton) such that the driver 324 turns off the first changeover switch SW1.

FIG. 8B illustrates the control method of the slope detection controller according to the present invention. A schematic diagram of a control error signal circuit of the third embodiment. In FIG. 8B, the pulse width modulation generator 325 further includes an error amplifier 321 and a first comparator 322. The slope detection controller 33 is coupled between the error amplifier 321 and the first comparator 322 for providing the control signal ctrl to control the error signal ERR of the error amplifier 321 to control the pulse width modulation generator 325 to stop providing the pulse wave. The width modulation signal pwm is forcibly turning off the ongoing conduction period, so that the driver 324 turns off the first switching switch SW1. In this embodiment, the control signal ctrl controls the error signal ERR to represent that the control signal ctrl can cause the error signal ERR provided by the error amplifier 321 to be pulled up or down to affect the pulse width modulation signal pwm. produce. In other embodiments, the control signal ctrl may also be summed with the error signal ERR or other various operations, and is not limited thereto.

8C is a schematic diagram of a control ramp signal circuit of a third embodiment of a control method of a slope detection controller according to the present invention. In FIG. 8C, the pulse width modulation generator 325 further includes a ramp signal generator 326. The first input end of the first comparator 322 is coupled to the error amplifier 321 , and the second input end of the first comparator 322 is coupled to the ramp signal generator 326 . The slope detection controller 33 is coupled to the ramp signal generator 326 for providing the control signal ctrl to control the ramp signal ramp of the ramp signal generator 326 to control the pulse width modulation generator 325 to stop providing the pulse width modulation. The change signal pwm is forcibly cutting off the ongoing conduction period, so that the driver 324 turns off the first changeover switch SW1. Similar to FIG. 8B, in FIG. 8C, the control signal ctrl controls the meaning of the ramp signal ramp: the control signal ctrl can cause the ramp signal ramp to be pulled up or down to affect the pulse width modulation signal pwm. produce. In its In the embodiment, the control signal ctrl may also be summed with the ramp signal ramp or other various operations, and is not limited thereto.

Another embodiment of the present invention is a slope of a power converter Detection control method. Please refer to FIG. 9. FIG. 9 is a flow chart showing a method for controlling the slope of the power converter of the embodiment. For the description, please refer to FIG. 3 and FIG. 4 together. In step S905, the slope detecting unit 41 is coupled to the output end of the power converter 300 and the output control unit 42 to receive the output voltage Vout of the power converter. In step S910, the method uses the slope detecting unit 41 to provide the slope detecting signal SD according to the output voltage Vout. In step S915, the method uses the output control unit 42 to generate the control signal ctrl. When the slope detection signal SD exceeds the preset value STL, the method generates the control signal ctrl according to the slope detection signal SD. In step S920, the method provides a control signal ctrl to control the power converter 300.

Compared with the prior art, the power converter and its slope detection according to the present invention The test controller and method can directly cut off the ongoing conduction period by detecting the slope of the output voltage and using the open loop control to effectively suppress the output voltage overshoot at the moment when the load current is converted from a heavy load to a light load. This phenomenon can cause the output voltage of the power converter to not continue to overshoot.

With the detailed description of the above preferred embodiments, it is hoped that the description will be more clearly described. The scope and spirit of the present invention is not limited by the preferred embodiments disclosed herein. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed.

300‧‧‧Power Converter

31‧‧‧Output level

32‧‧‧ Pulse width modulation control unit

321‧‧‧Error amplifier

322‧‧‧First comparator

323‧‧‧Time Signal Generator

324‧‧‧ drive

329‧‧‧Compensation unit

33‧‧‧Slope Detection Controller

Cout‧‧‧ output capacitor

Ctrl‧‧‧ control signal

ERR‧‧‧ error signal

ESR‧‧‧ equivalent series resistance

PHASE‧‧‧ phase node

IL‧‧‧Inductor Current

Iload‧‧‧ load current

Vin‧‧‧Input voltage

Vout‧‧‧ output voltage

UG‧‧‧first switch signal

LG‧‧‧Second switch signal

REF‧‧‧ reference signal

Ramp‧‧‧ ramp signal

SW1‧‧‧ first switch

SW2‧‧‧Second switch

R‧‧‧resistance

C‧‧‧ capacitor

Claims (15)

A slope detecting controller for a power converter includes: a slope detecting unit that receives an output voltage of the power converter, and generates a slope detecting signal according to the output voltage; and an output control unit coupled to the a slope detecting unit, and providing a control signal according to the slope detecting signal to control the power converter; wherein one of the power converters receives the control signal and a time signal respectively, and the control signal is prioritized Greater than the time signal. The slope detection controller of claim 1, wherein the output control unit generates the control signal when the slope detection signal exceeds a predetermined value. The slope detection controller of claim 1, wherein the driver generates a switching signal according to the control signal. The slope detection controller of claim 1, wherein the control signal is used to turn off an on-time signal of a time signal generator of the power converter. The slope detection controller of claim 4, wherein the control signal is used to cut off a pulse width modulation signal of the power converter. A power converter includes: an output stage including a first switch; a pulse width modulation control unit coupled to the output stage and controlling operation of the first switch of the output stage; and a slope detection a measurement controller coupled to the pulse width modulation control unit for generating a slope detection signal according to an output voltage of the power converter, and generating a control according to the slope detection signal The signal is controlled such that the pulse width modulation control unit controls the first switch to be closed; wherein the pulse width modulation control unit includes a driver coupled to the slope detection controller and the first switch The switch receives the control signal and a time signal respectively, and the priority of the control signal is greater than the time signal. The power converter of claim 6, wherein the output stage further comprises a second switch, the first switch is an upper bridge switch, and the second switch is a lower bridge switch. The power converter of claim 6, wherein the driver generates a switch signal according to the control signal. The power converter of claim 6, wherein the pulse width modulation control unit comprises a time signal generator, the slope detection controller is coupled to the time signal generator, such that the control signal controls the The time signal generator stops providing an on time signal to turn off the first switch. The power converter of claim 6, wherein the pulse width modulation control unit comprises a pulse width modulation generator, and the slope detection controller is coupled to the pulse width modulation generator. The control signal controls the pulse width modulation generator to stop providing a pulse width modulation signal to turn off the first switching switch. The power converter of claim 10, wherein the pulse width modulation generator comprises an error amplifier and a first comparator, the slope detection controller is coupled to the error amplifier and the first Between the comparators, the control signal is used to affect an error signal of the error amplifier, so that the pulse width modulation generator stops providing the pulse width modulation signal. The power converter of claim 10, wherein the pulse width modulation is produced The generator includes an error amplifier, a first comparator, and a ramp signal generator. The first input of the first comparator is coupled to the error amplifier, and the second input of the first comparator is coupled. The ramp signal generator is coupled to the ramp signal generator to use the control signal to affect a ramp signal of the ramp signal generator to cause the pulse width modulation generator The pulse width modulation signal is stopped. The power converter of claim 6, wherein the slope detection controller comprises a slope detecting unit and an output control unit, wherein the slope detecting unit is a differential circuit to provide a slope detecting signal. The output control unit generates the control signal according to the slope detection signal. A slope detection control method for a power converter includes the steps of: receiving an output voltage of the power converter; providing a slope detection signal according to the output voltage; and generating a control signal according to the slope detection signal to control The power converter; wherein the driver of the power converter receives the control signal and a time signal respectively, and the priority of the control signal is greater than the time signal. The slope detection control method of claim 14, wherein the control signal is generated when the slope detection signal exceeds a predetermined value.