CN-121984453-A - Error amplifier and converter system for peak current mode control

CN121984453ACN 121984453 ACN121984453 ACN 121984453ACN-121984453-A

Abstract

The invention provides an error amplifier and converter system for peak current mode control. The error amplifier comprises a transconductance amplifier, a voltage clamping module, a voltage-current converter, a slope compensation module, a current clamping module and a mirror tube, wherein the negative end of the transconductance amplifier is used for loading feedback voltage, the positive end of the transconductance amplifier is used for loading reference voltage, the output end of the transconductance amplifier, the output end of the voltage clamping module and the input end of the voltage-current converter are electrically connected, the voltage-current converter generates error current, the slope compensation module is used for performing slope compensation on the error current to generate compensated current, the output end of the slope compensation module, the output end of the current clamping module and the positive end of the high-side comparator are electrically connected with a second reference node, and the mirror tube is used for enabling comparison voltage to be loaded to the positive end of the high-side comparator. The error amplifier provided by the invention can realize more stable mode switching and more accurate current limiting control.

Inventors

LI YONGYUAN
YU LINYUN
WU JUNPENG
GUO WEI
ZHU GUANGQIAN
QIAN LIBO
ZHU ZHANGMING

Assignees

西安电子科技大学

Dates

Publication Date: 20260505
Application Date: 20251231

Claims (10)

1. The error amplifier for peak current mode control is characterized by comprising a transconductance amplifier, a voltage clamping module, a voltage-to-current converter, a slope compensation module, a current clamping module and a mirror tube; The negative end of the transconductance amplifier is used for loading feedback voltage, and the positive end of the transconductance amplifier is used for loading reference voltage; the voltage clamping module is used for carrying out voltage clamping control on the error voltage output by the transconductance amplifier so as to control the swing amplitude of the current-limiting reference voltage of the first reference node; The voltage-current converter is used for generating error current according to the voltage of the first reference node, the slope compensation module is used for performing slope compensation on the error current to generate compensated current, the output end of the slope compensation module and the output end of the current clamping module are electrically connected with the second reference node, and the current clamping module is used for performing current clamping control on the compensated current output by the slope compensation module so as to control the swing amplitude of the current-limiting reference current output by the second reference node; the mirror tube is used for generating comparison voltage according to the current-limiting reference current and enabling the comparison voltage to be loaded to the positive end of the high-side comparator.
2. The error amplifier for peak current mode control according to claim 1, wherein the current clamp module is configured to cause the current-limiting reference current output by the second reference node to be a lower limit current when the compensated current output by the slope compensation module is lower than a lower limit current, and to cause the current-limiting reference current output by the second reference node to be an upper limit current when the compensated current output by the slope compensation module is greater than an upper limit current.
3. The error amplifier for peak current mode control according to claim 2, wherein the current clamp module comprises a current low clamp sub-module and a current high clamp sub-module; the current low-clamping submodule is enabled to output a lower limit current to the second reference node when the compensated current output by the slope compensation module is lower than the lower limit current; the current high clamping submodule is enabled to output an upper limit current to the second reference node when the compensated current output by the slope compensation module is higher than the upper limit current.
4. The error amplifier for peak current mode control according to claim 3, wherein the current clamp module further comprises a bypass sub-module that causes the compensated current output by the slope compensation module to be loaded to the second reference node through the bypass sub-module when the compensated current is between a lower limit current and an upper limit current.
5. The error amplifier for peak current mode control of claim 3, wherein the current clamp module comprises a first P-type transistor to a fourth P-type transistor, a first N-type transistor to a fourth N-type transistor, a first constant current source, a second constant current source, a first mirror tube and a second mirror tube, wherein the first mirror tube and the second mirror tube are used for generating the compensated current; The source electrode of the first N-type transistor, the source electrode of the second N-type transistor, the source electrode of the third N-type transistor, the source electrode of the fourth N-type transistor, the output end of the first constant current source and the output end of the second constant current source are all used for loading ground voltage; The drain electrode of the first P-type transistor, the drain electrode of the first mirror image transistor, the input end of the first constant current source and the grid electrode of the second P-type transistor are electrically connected with each other; The drain electrode of the second P-type transistor, the drain electrode of the second mirror image transistor, the drain electrode of the first N-type transistor, the grid electrode of the second N-type transistor and the drain electrode of the third N-type transistor are electrically connected with each other; the drain electrode of the third P-type transistor, the grid electrode of the fourth P-type transistor and the drain electrode of the second N-type transistor are electrically connected with each other; The drain electrode of the fourth P-type transistor, the gate electrode of the third N-type transistor, the gate electrode of the fourth N-type transistor, the drain electrode of the fourth N-type transistor and the input end of the second constant current source are electrically connected.
6. The error amplifier for peak current mode control according to claim 1, further comprising a compensator electrically connected to an output of the transconductance amplifier.
7. The error amplifier for peak current mode control according to claim 1, further comprising an oscillator mask circuit and a zero crossing detection circuit.
8. A peak current mode controlled converter system comprising an error amplifier as claimed in any one of claims 1 to 7.
9. The converter system of claim 8, further comprising a voltage conversion circuit, a sampling circuit, and a control circuit; The voltage conversion circuit comprises a high-side switch, a low-side switch, an inductor, a first resistor, a second resistor, a third resistor and a fourth resistor and a capacitor, wherein the first end of the high-side switch is used for loading input voltage, the second end of the high-side switch, the first end of the low-side switch and the first end of the inductor are electrically connected with an inductor current sampling node, the second end of the inductor, the first end of the fourth resistor, the first end of the third resistor and the first end of the first resistor are electrically connected with an output end, the second end of the fourth resistor and the first end of the capacitor are electrically connected with each other, and the second end of the first resistor and the first end of the second resistor are electrically connected with a feedback sampling node; the sampling circuit comprises a sampling resistor, wherein a first end of the sampling resistor is electrically connected with a second end of the high-side switch to sample inductance current flowing through the second end of the high-side switch; the positive end of the error amplifier is used for loading reference voltage, and the negative end of the error amplifier is electrically connected with the feedback sampling node; The control circuit comprises a high-side comparator, a control unit and a driver, wherein the positive end of the Gao Bianbi comparator is electrically connected with the output end of the mirror tube of the error amplifier, the negative end of the Gao Bianbi comparator is electrically connected with the second end of the sampling resistor, the control unit is used for generating a control signal according to the comparison result of the high-side comparator, and the driver is used for controlling the high-side switch and the low-side switch to be selectively conducted according to the control signal.
10. The transducer system of claim 9, wherein the output of the transducer is coupled to the output of the transducer, the converter system further includes an oscillator electrically connected with the control unit.

Description

Error amplifier and converter system for peak current mode control Technical Field The invention belongs to the technical field of analog integrated circuits, and particularly relates to an error amplifier and converter system for peak current mode control. Background In a conventional peak current mode control system, in order to realize mode switching under light and heavy load conditions, a scheme of setting a voltage high clamp and a voltage low clamp at an output end of an error amplifier is generally used. Under the light load condition, the system enters a DCM mode through the cooperation of the low-voltage clamp and the oscillator control logic, and under the heavy load condition, the high-side current limiting protection function is realized through the cooperation of the high-voltage clamp and the high-side comparator. The voltage clamp only limits the swing of the output voltage of the error amplifier, and cannot directly restrict the output current of the error amplifier. Under the light load condition, the minimum value of the peak inductive current is difficult to be limited effectively due to lack of control on the current, so that the inductive current pulse is unstable when the light load works, and the overall efficiency of the system is affected. Under the heavy load condition, only the output end of the error amplifier is provided with a voltage high clamp, the current generated by the output voltage through the voltage-current converter is overlapped with the slope compensation current, and then the current is compared with the inductance current obtained by sampling. It should be noted that the information disclosed in the above background section is only for enhancing understanding of the background of the invention and thus may include information that does not form the prior art that is already known to those of ordinary skill in the art. Disclosure of Invention In order to solve the above problems in the prior art, the present invention provides an error amplifier and converter system for peak current mode control, which realizes more stable mode switching and more accurate current limiting control. The technical problems to be solved by the invention are realized by the following technical scheme: In a first aspect, the invention provides an error amplifier for peak current mode control, comprising a transconductance amplifier, a voltage clamping module, a voltage-to-current converter, a slope compensation module, a current clamping module and a mirror tube; The negative end of the transconductance amplifier is used for loading feedback voltage, and the positive end of the transconductance amplifier is used for loading reference voltage; the voltage clamping module is used for carrying out voltage clamping control on the error voltage output by the transconductance amplifier so as to control the swing amplitude of the current-limiting reference voltage of the first reference node; The voltage-current converter is used for generating error current according to the voltage of the first reference node, the slope compensation module is used for performing slope compensation on the error current to generate compensated current, the output end of the slope compensation module and the output end of the current clamping module are electrically connected with the second reference node, and the current clamping module is used for performing current clamping control on the compensated current output by the slope compensation module so as to control the swing amplitude of the current-limiting reference current output by the second reference node; the mirror tube is used for generating comparison voltage according to the current-limiting reference current and enabling the comparison voltage to be loaded to the positive end of the high-side comparator. In one embodiment of the invention, the current clamping module is configured to enable the current limiting reference current output by the second reference node to be a lower limit current when the compensated current output by the slope compensation module is lower than a lower limit current, and enable the current limiting reference current output by the second reference node to be an upper limit current when the compensated current output by the slope compensation module is greater than an upper limit current. In one embodiment of the invention, the current clamping module comprises a current low clamping sub-module and a current high clamping sub-module; the current low-clamping submodule is enabled to output a lower limit current to the second reference node when the compensated current output by the slope compensation module is lower than the lower limit current; the current high clamping submodule is enabled to output an upper limit current to the second reference node when the compensated current output by the slope compensation module is higher than the upper limit current. In one embodiment of the present invention, the current clampi