Slope compensation measurement circuit, method and switching power supply chip

Abstract

The present application provides a slope compensation measurement circuit, method and switching power supply chip, which relates to the technical field of switching power supply. The slope compensation measurement circuit includes: a slope compensation circuit and a measurement circuit, wherein the slope compensation circuit is used to perform slope compensation on a preset power converter; the first input end of the measurement circuit is connected to the measurement end of the slope compensation circuit, the second input end of the measurement circuit receives a preset reference voltage, and the control end of the measurement circuit is used to receive a preset measurement signal, so that the measurement circuit compares the preset reference voltage with the voltage of the measurement slope signal of the measurement end, generates a measurement clock signal, and the clock signal output end of the measurement circuit is used to output a measurement clock signal to calculate the slope compensation voltage value of the slope compensation circuit according to the measurement clock signal and the preset reference voltage. The present application can accurately measure the slope compensation voltage.

Description

Technical Field

[0001] The present application relates to the technical field of switching power supplies, and in particular to a slope compensation measurement circuit, method and switching power supply chip. Background Art

[0002] Power converters using peak current control mode have significant advantages such as fast loop response and easy compensation circuit design. Therefore, current control mode is widely used in boost, buck, and buck-boost switching power supply chips.

[0003] When the switching duty cycle of a peak current controlled power converter is greater than 50%, the error between the average and peak values ​​of the inductor current will increase, resulting in loop instability and subharmonic oscillation in the output voltage. This problem is more significant when the inductor current is small. Therefore, a power converter using current control mode requires slope compensation to stabilize the loop.

[0004] The slope compensation circuit provides a slope compensation voltage for the power converter, so that the influence of the current closed loop can be better controlled. However, the measurement of the slope compensation amount has always troubled designers. The conventional slope compensation test method is to directly output the ramp signal to the corresponding test pin and directly measure the slope compensation amount with a voltmeter. However, the trace resistance and parasitic inductance in the chip will affect the accuracy of the measurement result. Summary of the invention

[0005] The purpose of the present application is to provide a slope compensation measurement circuit, method and switching power supply chip to address the deficiencies in the above-mentioned prior art, so as to accurately measure the slope compensation voltage.

[0006] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0007] In a first aspect, an embodiment of the present application provides a slope compensation measurement circuit, the slope compensation measurement circuit comprising: a slope compensation circuit and a measurement circuit, wherein the slope compensation circuit is used to perform slope compensation on a preset power converter;

[0008] The first input terminal of the measurement circuit is connected to the measurement terminal of the slope compensation circuit, the second input terminal of the measurement circuit receives a preset reference voltage, the control terminal of the measurement circuit is used to receive a preset measurement signal, so that the measurement circuit compares the preset reference voltage with the voltage of the measurement ramp signal at the measurement terminal to generate a measurement clock signal, and the clock signal output terminal of the measurement circuit is used to output the measurement clock signal to calculate the slope compensation voltage value of the slope compensation circuit according to the measurement clock signal and the preset reference voltage.

[0009] Optionally, the measurement circuit includes: a first voltage replication module, a first comparator and a divide-by-two frequency counter;

[0010] The input end of the first voltage replication module serves as the first input end of the measurement circuit, and the control end of the first voltage replication module serves as the control end of the measurement circuit;

[0011] The output end of the first voltage replication module is connected to the first input end of the first comparator, and the second input end of the first comparator serves as the second input end of the measurement circuit, so that the first comparator compares the preset reference voltage and the voltage of the measurement ramp signal at the measurement end to obtain a comparison result; the output end of the first comparator is connected to the input end of the divide-by-two counter, so that the divide-by-two counter performs a flip count on the comparison result to generate the measurement clock signal, and the first output end of the divide-by-two counter serves as the clock signal output end of the measurement circuit.

[0012] Optionally, the divide-by-two frequency counter comprises: a first inverter and a D flip-flop;

[0013] The input end of the first inverter serves as the input end of the divide-by-two counter, the output end of the first inverter is connected to the clock end of the D flip-flop, and the input end of the D flip-flop is connected to the output end of the D flip-flop as the first output end of the divide-by-two counter.

[0014] Optionally, the first inverter outputs a first charge and discharge control signal according to the comparison result, and the output end of the first inverter is also connected to the charge and discharge control end of the slope compensation circuit to control the charge and discharge of the slope compensation circuit based on the first charge and discharge control signal.

[0015] Optionally, the slope compensation circuit includes: a voltage generating module, a second voltage replicating module, an adder, an error amplifier, a second comparator, and a logic control module;

[0016] The input end of the voltage generation module is connected to a preset power supply, the output end of the voltage generation module is connected to the input end of the second voltage replication module, and the control end of the second voltage replication module is used to receive a compensation control signal;

[0017] The output end of the second voltage replication module is connected to the first input end of the adder, the second input end of the adder is used to receive the current sampling signal of the preset power converter, and the output end of the adder is connected to the positive input end of the second comparator;

[0018] The positive input terminal of the error amplifier is used to receive the preset reference voltage, the negative input terminal of the error amplifier is used to receive the output voltage of the preset power converter, and the output terminal of the error amplifier is connected to the negative input terminal of the second comparator;

[0019] The output end of the second comparator is connected to the input end of the logic control module, the output end of the logic control module is connected to the control end of the voltage generation module, and the control end of the voltage generation module serves as the charge and discharge control end of the slope compensation circuit;

[0020] The first voltage copy module and the second voltage copy module have the same structure.

[0021] Optionally, the first voltage replication module includes: a first MOS transistor, a second MOS transistor and a resistor;

[0022] The first end of the first MOS tube serves as the input end of the first voltage replication module, the first MOS tube is connected to the first end of the second MOS tube, and the second end of the second MOS tube is grounded through the resistor;

[0023] The gate of the second MOS transistor serves as a control terminal of the first voltage replication module, and the connection point between the second MOS transistor and the resistor serves as an output terminal of the first voltage replication module;

[0024] The size of the first MOS tube and the resistance value of the resistor are the same as the first MOS tube and the resistance value of the resistor in the second voltage replication module.

[0025] Optionally, the slope compensation circuit further comprises: a selection controller;

[0026] The first input terminal and the second input terminal of the selection controller are both used as the charge and discharge control terminals of the slope compensation circuit, the first input terminal of the selection controller is connected to the second output terminal of the two-division frequency counter, and the second input terminal of the selection controller is connected to the output terminal of the logic control module;

[0027] The output end of the selection controller is connected to the control end of the voltage generating module, and the selection end of the selection controller is used to receive the preset measurement signal to determine, based on the preset measurement signal, to control the voltage generating module to charge and discharge according to the first charge and discharge control signal output by the two-division counter or the second charge and discharge control signal output by the logic control module.

[0028] Optionally, the slope compensation circuit further includes: a second inverter;

[0029] The input end of the second inverter is connected to the output end of the logic control module, and the output end of the second inverter is connected to the control end of the second voltage replication module to provide the compensation control signal to the second voltage replication module.

[0030] In a second aspect, an embodiment of the present application further provides a slope compensation measurement method, which is applied to the slope compensation measurement circuit as described in any one of the first aspects, and the method includes:

[0031] Controlling the measuring circuit to enter a measuring mode according to a preset measuring signal;

[0032] generating a measurement clock signal according to a comparison result between a voltage of a measurement ramp signal measured by the measurement circuit and a preset reference voltage;

[0033] The slope compensation voltage of the slope compensation circuit is calculated according to the frequency of the measurement clock signal and the preset reference voltage.

[0034] In a third aspect, an embodiment of the present application further provides a switching power supply chip, the switching power supply chip comprising: the slope compensation measurement circuit and the power converter as described in any one of the first aspects;

[0035] An output end of the slope compensation circuit in the slope compensation measurement circuit is connected to a control end of the power converter.

[0036] The beneficial effects of this application are:

[0037] The slope compensation measurement circuit, method and switching power supply chip provided by the present application, when the slope compensation voltage is output to the measurement end through the measurement voltage, the wiring resistance, parasitic capacitance and parasitic inductance in the chip will not affect the frequency of the measurement clock signal. Therefore, based on the slope compensation measurement circuit, an accurate slope compensation voltage value can be obtained, and the measurement accuracy of the slope compensation voltage value is improved, so that the slope compensation voltage value can be easily adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 An equivalent circuit diagram for measuring the existing slope compensation;

[0040] Figure 2 A structural diagram of a slope compensation measurement circuit provided in an embodiment of the present application;

[0041] Figure 3 A schematic diagram of a flow chart of a slope compensation measurement method provided in an embodiment of the present application;

[0042] Figure 4 A schematic diagram of the structure of a measurement circuit provided in an embodiment of the present application;

[0043] Figure 5 A circuit schematic diagram of a slope compensation measurement circuit provided in an embodiment of the present application;

[0044] Figure 6 A signal waveform diagram provided for an embodiment of the present application;

[0045] Figure 7 A schematic diagram of the structure of a switching power supply chip provided in an embodiment of the present application.

[0046] Description of reference numerals:

[0047] 100-slope compensation measurement circuit; 10-slope compensation circuit; 11-voltage generation module; 12-second voltage replication module; 13-adder; 14-error amplifier; 15-second comparator; 16-logic control module; 17-selection controller; 18-second inverter; 20-measurement circuit; 21-first voltage replication module; 22-first comparator; 23-two-division counter; 231-first inverter; 232-D flip-flop; 200-power converter. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0049] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0050] In addition, the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0051] It should be noted that, in the absence of conflict, the features in the embodiments of the present application may be combined with each other.

[0052] Figure 1 The equivalent circuit diagram of the existing slope compensation measurement is as follows: Figure 1 As shown, when switch S1 is closed and switch S2 is open, the current source I DC The capacitor C1 is charged; when the switch S2 is closed and the switch S1 is opened, the capacitor C1 is discharged, thereby forming a ramp signal V C . The ramp signal V C Through the wiring resistance R P1 and parasitic capacitance C P After being filtered, the signal V transmitted to the test pin TEST PIN PIN The ramp signal V C different.

[0053] In addition, there is a parasitic inductance L between the power ground inside the chip and the voltage of the ground pin GND PIN outside the chip. P and trace resistance R P2 Therefore, the power ground inside and outside the chip will also have errors, so the voltage V measured at the test pin PIN The actual ramp voltage V generated inside the chip C At the same time, the wiring used for testing and the internal resistance of the voltmeter will cause measurement errors.

[0054] like Figure 1 As shown, after the charging and discharging of capacitor C1, the ramp signal V C Equivalent to Figure 1 The reference ramp signal V A , however, the signal V delivered to the test pin PIN Equivalent to Figure 1 The measured ramp signal V B It can be seen that the ramp signal VC Taking measurements will result in large errors.

[0055] The specific implementation of the slope compensation measurement circuit, method and switching power supply chip provided by the present application is described below in conjunction with the embodiments.

[0056] Figure 2 The structure diagram of the slope compensation measurement circuit provided in the embodiment of the present application is as follows: Figure 2 As shown, the slope compensation measurement circuit 100 comprises: a slope compensation circuit 10 and a measurement circuit 20, wherein the slope compensation circuit 10 is used to perform slope compensation on a preset power converter.

[0057] The first input terminal of the measuring circuit 20 is connected to the measuring terminal of the slope compensation circuit 10, and the second input terminal of the measuring circuit 20 receives a preset reference voltage V ref The control terminal of the measuring circuit 20 is used to receive a preset measuring signal tm_en, so that the measuring circuit 20 measures the preset reference voltage V ref and the voltage V of the measuring ramp signal at the measuring end slope_cp The measurement clock signal CLK_out is generated by comparison. The clock signal output terminal of the measurement circuit 20 is used to output the measurement clock signal CLK_out. ref The slope compensation voltage value of the slope compensation circuit 10 is calculated.

[0058] Figure 3 A schematic diagram of a flow chart of a slope compensation measurement method provided in an embodiment of the present application, such as Figure 3 As shown, the method may include:

[0059] S101: Controlling a measurement circuit to enter a measurement mode according to a preset measurement signal.

[0060] S102: Generate a measurement clock signal according to a comparison result between a voltage of a measurement ramp signal measured by a measurement circuit and a preset reference voltage.

[0061] S103: Calculating a slope compensation voltage of the slope compensation circuit according to the frequency of the measurement clock signal and a preset reference voltage.

[0062] In this embodiment, the slope compensation circuit 10 is used to generate a slope compensation voltage. The slope compensation circuit 10 is also used to receive a current sampling signal V obtained by sampling the inductor current of the power converter. S , and the feedback voltage signal V obtained by sampling the output voltage of the power converter FB , and controls the power converter to perform power conversion according to the control signal generated by the compensation signal of the slope compensation voltage, the current sampling signal and the feedback voltage signal.

[0063] The control end of the measurement circuit 20 is used to receive a preset measurement signal tm_en, and control whether the measurement circuit enters a measurement mode according to the preset measurement signal tm_en. When the preset measurement signal tm_en=0, the measurement circuit 20 does not work. When the preset measurement signal tm_en=1, the measurement circuit 20 enters a measurement mode.

[0064] The measuring circuit 20 is connected to the measuring end of the slope compensation circuit 10, and is used to copy the slope compensation voltage generated by the slope compensation circuit 10, and generate a measuring ramp signal at the first input end. The second input end of the measuring circuit 20 is used to input a preset reference voltage V ref , the measuring circuit 20 measures the voltage V of the ramp signal slope_cp and preset reference voltage V ref A comparison is performed, and a measurement clock signal CLK_out is generated according to the comparison result.

[0065] The charge and discharge control terminal of the slope compensation circuit 10 is used to receive the charge and discharge control signal. In the process of charging according to the charge and discharge control signal, the slope compensation circuit 10 generates a gradually increasing slope compensation voltage with a fixed slope. The measurement circuit 20 measures the gradually increasing measurement slope signal voltage V slope_cp , when measuring the voltage of the ramp signal V slope_cp In the process of gradual increase, if the voltage V of the ramp signal is measured slope_cp Less than the preset reference voltage V ref , the comparison result is 0 (or 1), when the voltage V of the ramp signal is measured slope_cp The peak value is greater than or equal to the preset reference voltage V ref , the comparison result is 1 (or 0).

[0066] When the slope compensation circuit 10 performs continuous charging and discharging based on the charging and discharging control signal, the measuring circuit 20 performs level flipping according to the comparison result 1 (or 0) to obtain a measuring clock signal.

[0067] Since the measuring circuit 20 performs level flipping according to the comparison result 1 (or 0), the charging time of the slope compensation circuit 10 based on the charge and discharge control signal determines the time when the comparison result 1 (or 0) appears, which also determines the time when the measuring circuit 20 performs level flipping according to the comparison result 1 (or 0). The frequency of the measurement clock signal is determined according to the level flipping time. f CLK_out , the duty cycle of the measured clock signal is 50%.

[0068] According to the preset reference voltage V ref and measure the frequency of the clock signal f CLK_out The voltage V of the measured ramp signal can be calculatedslope_cp The slope k is based on the voltage V of the measured ramp signal. slope_cp The slope k and the preset reference voltage V ref , the slope compensation voltage value can be calculated.

[0069] For example, the preset reference voltage V ref and measure the frequency of the clock signal f CLK_out The relationship can be expressed as:

[0070] V ref = k / 2 f CLK_out

[0071] Then measure the voltage V of the ramp signal slope_cp The slope k=2V ref · f CLK_out .

[0072] If the switching frequency of the preset power converter is f sw , then the calculation formula of the slope compensation voltage value can be expressed as:

[0073] V slope_peak = k·t HS_on = k·d·T=2· f CLK_out ·V out ·V ref / f sw ·V in

[0074] Among them, t HS_on is the on-time of the high-side power tube, d is the duty cycle, and T is the switching period.

[0075] In one possible implementation, Figure 4 A schematic diagram of the structure of the measurement circuit provided in the embodiment of the present application is shown in FIG. Figure 4 As shown, the measurement circuit 20 may include: a first voltage replication module 21 , a first comparator 22 and a divide-by-two frequency counter 23 .

[0076] The input end of the first voltage replication module 21 is used as the first input end of the measurement circuit 20, and the control end of the first voltage replication module 21 is used as the control end of the measurement circuit 20; the output end of the first voltage replication module 21 is connected to the first input end of the first comparator 22, and the second input end of the first comparator 22 is used as the second input end of the measurement circuit 20, so that the first comparator 22 is connected to the preset reference voltage V ref and the voltage V of the measuring ramp signal at the measuring end slope_cpThe output end of the first comparator 22 is connected to the input end of the divide-by-two counter 23, so that the divide-by-two counter 23 performs a flip count on the comparison result to generate a measurement clock signal, and the first output end of the divide-by-two counter 23 serves as the clock signal output end of the measurement circuit 20.

[0077] In this embodiment, the control end of the first voltage replication module 21 is used to receive a preset measurement signal tm_en, and control whether the first voltage replication module 21 enters a measurement mode according to the preset measurement signal tm_en. When the preset measurement signal tm_en=0, the first voltage replication module 21 does not work. When the preset measurement signal tm_en=1, the first voltage replication module 21 enters a measurement mode.

[0078] The first voltage replication module 21 is connected to the measuring end of the slope compensation circuit 10, and is used to replicate the slope compensation voltage generated by the slope compensation circuit 10 to generate a measurement slope signal. The output end of the first voltage replication module 21 is connected to the first input end of the first comparator 22, and the second input end of the first comparator 22 is used to input a preset reference voltage V ref The first comparator 22 measures the voltage V of the ramp signal slope_cp and preset reference voltage V ref Perform a comparison and generate a comparison result.

[0079] The output end of the first comparator 22 is connected to the input end of the divide-by-two frequency counter 23. The divide-by-two frequency counter 23 performs flip counting according to the comparison result. The divide-by-two frequency counter 23 counts to 0 or 1 according to the comparison result.

[0080] For example, the positive input terminal of the first comparator 22 inputs a preset reference voltage V ref The negative input terminal of the first comparator 22 inputs the voltage V of the measuring ramp signal slope_cp , if the voltage V of the ramp signal is measured slope_cp Less than the preset reference voltage V ref , the first comparator 22 outputs the comparison result 1. If the voltage V of the measured ramp signal slope_cp Greater than or equal to the preset reference voltage V ref , the first comparator 22 outputs a comparison result of 0.

[0081] In the process of continuous charging and discharging of the slope compensation circuit 10 based on the charge and discharge control signal, each time the first comparator 22 outputs a comparison result of 0, the count of the divide-by-two counter 23 changes by 1. For example, if the initial output of the divide-by-two counter 23 is 0, when the comparison result 0 is received for the first time, the divide-by-two counter 23 flips and outputs 1. When the comparison result 1 is received for the second time, the divide-by-two counter 23 flips and outputs 0. Based on this, the divide-by-two counter 23 outputs a measurement clock signal composed of 0 and 1.

[0082] In some embodiments, the negative input terminal of the first comparator 22 inputs a preset reference voltage V ref The positive input terminal of the first comparator 22 inputs the voltage V of the measuring ramp signal slope_cp The divide-by-two counter 23 is a D flip-flop, the output end of the first comparator 22 is connected to the clock end of the D flip-flop, and the input end of the D flip-flop is connected to the output end of the D flip-flop.

[0083] If the voltage V of the ramp signal is measured slope_cp Less than the preset reference voltage V ref , the first comparator 22 outputs the comparison result 0. If the voltage V of the measured ramp signal slope_cp Greater than or equal to the preset reference voltage V ref , the first comparator 22 outputs a comparison result 1, and the D flip-flop outputs once when receiving the comparison result 1. When the D flip-flop receives the next comparison result 1, the output is flipped. In this way, each time the D flip-flop receives a comparison result 1, its output is flipped once to obtain a measurement clock signal.

[0084] In one possible implementation, Figure 5 The circuit schematic diagram of the slope compensation measurement circuit provided in the embodiment of the present application is as follows: Figure 5 As shown, the divide-by-two frequency counter 23 includes a first inverter 231 and a D flip-flop 232 .

[0085] The input end of the first inverter 231 is used as the input end of the divide-by-two counter 23 , the output end of the first inverter 231 is connected to the clock end of the D flip-flop 232 , and the input end of the D flip-flop 232 is connected to the output end of the D flip-flop 232 as the first output end of the divide-by-two counter 23 .

[0086] In this embodiment, if Figure 5 As shown, the positive input terminal of the first comparator 22 receives a preset reference voltage V ref The negative input terminal of the first comparator 22 receives the voltage V of the measuring ramp signal slope_cp , if the voltage V of the ramp signal is measured slope_cp Less than the preset reference voltage V ref, the first comparator 22 outputs the comparison result RST_n as 1, which is output as 0 after passing through the first inverter 231. If the voltage V of the measured ramp signal slope_cp Greater than or equal to the preset reference voltage V ref , the first comparator 22 outputs a comparison result RST_n of 0, which is output as 1 through the first inverter 231.

[0087] When the clock terminal CLK of the D flip-flop 232 receives 1, an output is performed. When the clock terminal of the D flip-flop 232 receives 1 next time, the output is flipped. In this way, each time the clock terminal of the D flip-flop 232 receives a 1, its output is flipped once to obtain a measurement clock signal.

[0088] For example, Figure 6 The signal waveform diagram provided in the embodiment of the present application is as follows: Figure 6 As shown, the slope compensation circuit 10 generates a gradually increasing slope compensation voltage with a fixed slope k during charging according to the charge and discharge control signal, and the measurement circuit 20 measures the gradually increasing measurement slope signal voltage V slope_cp , measure the voltage V of the ramp signal slope_cp The slope of the ramp signal is also k. When measuring the voltage V slope_cp The peak value is less than the preset reference voltage V ref When the comparison result output by the first comparator 22 is 1, the first inverter 231 outputs RST as 0 according to the comparison result 1. When the voltage V of the ramp signal is measured slope_cp The peak value is greater than or equal to the preset reference voltage V ref When , the comparison result output by the first comparator 22 is 0, and the first inverter 231 outputs RST as 1 according to the comparison result 0. In this way, each time the clock end of the D flip-flop 232 receives a 1, its output flips once to obtain a measurement clock signal.

[0089] In some embodiments, the first inverter 231 outputs a first charge and discharge control signal according to the comparison result, and the output end of the first inverter 231 is also connected to the charge and discharge control end of the slope compensation circuit 10 to control the charge and discharge of the slope compensation circuit based on the first charge and discharge control signal.

[0090] In this embodiment, in order to control the measurement circuit 20 to measure the voltage V of the ramp signal slope_cp and preset reference voltage V ref The comparison result outputs a measurement clock signal, and the slope compensation circuit 10 needs to be controlled to perform continuous charging and discharging. To this end, this embodiment directly uses the measurement circuit 20 to control the slope compensation circuit 10 to perform charging and discharging, so that the slope compensation measurement circuit can realize automatic slope compensation voltage measurement.

[0091] Specifically, when the first comparator 22 outputs the comparison result 0, the voltage V of the measuring ramp signal is determined. slope_cp The peak value is greater than or equal to the preset reference voltage V ref At this time, it is necessary to control the slope compensation circuit to discharge, and for this purpose, the first charge and discharge control signal is output through the output terminal of the first inverter 231. When the first comparator 22 outputs the comparison result 0, the first inverter 231 outputs the first charge and discharge control signal as a high level 1, controls the discharge path of the slope compensation circuit 10 to be turned on, and the slope compensation circuit 10 is discharged, and the voltage V of the ramp signal is measured. slope_cp becomes 0, the first comparator 22 outputs the comparison result 1, the first inverter 231 outputs the first charge and discharge control signal as a low level, controls the discharge path of the slope compensation circuit 10 to be turned off, the slope compensation circuit 10 is charged, and the voltage V of the ramp signal is measured. slope_cp The voltage starts to increase again, and the cycle repeats. The measuring circuit 20 outputs a measuring clock signal.

[0092] In one possible implementation, Figure 5 As shown, the slope compensation circuit 10 includes: a voltage generating module 11 , a second voltage replicating module 12 , an adder 13 , an error amplifier 14 , a second comparator 15 , and a logic control module 16 .

[0093] The input end of the voltage generation module 11 is connected to the preset power supply VDD, the output end of the voltage generation module 11 is connected to the input end of the second voltage replication module 12, and the control end of the second voltage replication module 12 is used to receive the compensation control signal HS_on; the output end of the second voltage replication module 12 is connected to the first input end of the adder 13, the second input end of the adder 13 is used to receive the current sampling signal of the preset power converter, and the output end of the adder 13 is connected to the positive input end of the second comparator 15; the positive input end of the error amplifier (Error Amplifier, EA) 14 is used to receive the preset reference voltage, the negative input end of the error amplifier 14 is used to receive the output voltage of the preset power converter, and the output end of the error amplifier 14 is connected to the negative input end of the second comparator 15; the output end of the second comparator 15 is connected to the input end of the logic control module 16, the output end of the logic control module 16 is connected to the control end of the voltage generation module 11, and the control end of the voltage generation module 11 serves as the charge and discharge control end of the slope compensation circuit; the first voltage replication module 21 and the second voltage replication module 12 have the same structure.

[0094] In this embodiment, if Figure 5As shown, the voltage generation module 11 may include: transistor Q1, transistor Q2, capacitor C1, resistor R1 and MOS tube M4, and the second voltage replication module 12 may include: MOS tube M2, MOS tube M5 and resistor R2, wherein the transistor Q2 and the resistor R1 form a voltage follower structure, and the MOS tube M4 is used to control the charging and discharging of the capacitor C1. When the MOS tube M4 is turned off, the capacitor C1 is charged, and when the MOS tube M4 is turned on, the capacitor C1 is discharged. The gates of the MOS tube M1 and the MOS tube M2 are connected to form a current mirror, and the MOS tube M5 is used to control whether the second voltage replication module 12 generates a slope compensation voltage V slope .

[0095] The working principle of the slope compensation circuit 10 is as follows:

[0096] When the measurement circuit 20 is not working, the slope compensation measurement circuit is in a normal working mode. In the initial state, the high-side power tube of the power converter is turned on, that is, HS_on=1, HS_off=0. At this time, the MOS tube M4 is closed, the MOS tube M5 is turned on, and the current source I DC The capacitor C1 is charged, and during the time when the high-side power tube is turned on, the voltage of the capacitor C1 rises by ΔV.

[0097] Since transistor Q2 and resistor R1 form a voltage follower structure, when the voltage at the emitter of transistor Q1, i.e. point A, rises by ΔV, the voltage at the emitter of transistor Q2, i.e. point B, also rises by ΔV, and the current flowing through resistor R1 is I R1 =ΔV / R1, MOS tube M1 and MOS tube M2 form a current mirror with a width-to-length ratio of n, so the current across the resistor R2 is I R2 =R2ΔV / R1. If the resistance of resistor R1 is the same as that of resistor R2, the final slope compensation signal voltage V slope =nΔV. The voltage of the slope compensation signal V slope , the current sampling signal CSA_out is added by the adder 13 to obtain the sum signal V sum The error amplifier 14 generates a voltage signal V according to the feedback voltage. FB and preset reference voltage V ref Generate comparison signal V COMP , when the sum signal V sum Higher than the comparison signal V COMP When HS_off=1, HS_on=0, the high-side power tube is turned off. At this time, MOS tube M4 is turned on, MOS tube M5 is turned off, and the voltage of the slope compensation signal V slope It is pulled down to ground by resistor R2. HS_on is reset to 1 when the next clock rising edge arrives.

[0098] The structures of the first voltage replication module 21 and the second voltage replication module 12 are completely consistent, so that the voltage V of the slope compensation signal is slope The slope compensation signal voltage V slope The voltage of the measuring ramp signal is exactly the same as V slope_cp .

[0099] It should be noted that when the measurement circuit 20 is not working, the slope compensation circuit 10 also needs to be charged and discharged according to the charge and discharge control signal. When HS_on=1, HS_off=0, the high-side power tube of the power converter is turned on, the slope compensation circuit 10 needs to provide a slope compensation voltage for the power converter. At this time, the slope compensation circuit 10 should be in a charging state; when HS_on=0, HS_off=1, the high-side power tube of the power converter is turned off, the slope compensation circuit 10 does not need to provide a slope compensation voltage for the power converter. At this time, the slope compensation circuit 10 should be in a discharging state. Therefore, the slope compensation circuit 10 can be controlled to be charged and discharged according to the second charge and discharge control signal HS_off output by the logic control module 16.

[0100] In some embodiments, Figure 5 As shown, the first voltage replication module 21 includes: a first MOS transistor M3, a second MOS transistor M6 and a resistor R3.

[0101] The first end of the first MOS tube M3 serves as the input end of the first voltage replication module 21, the second end of the first MOS tube M3 is connected to the first end of the second MOS tube M6, and the second end of the second MOS tube M6 is grounded through the resistor R3; the gate of the second MOS tube M6 serves as the control end of the first voltage replication module 21, and the connection point between the second MOS tube M6 and the resistor R3 serves as the output end of the first voltage replication module 21; the size of the first MOS tube M3 and the resistance value of the resistor R3 are the same as the resistance values ​​of the MOS tube M5 and the resistor R2 in the second voltage replication module 12. The first end and the second end of the MOS tube are the source and the drain of the MOS tube respectively.

[0102] In this embodiment, the working principle of the first voltage replication module 21 is as follows: after the measurement circuit 20 enters the measurement mode, tm_en=1, the second MOS tube M6 is turned on, the MOS tube M4 is connected by the first charge and discharge control signal RST, the gates of the MOS tube M2 and the first MOS tube M3 are connected to form a 1:1 current mirror tube, the resistance value of the resistor R3 is the same as that of the resistor R2, and during the time when the high-side power tube is turned on, the voltage drop generated on the resistor R3 is also nΔV, thereby generating a voltage V of the replicated measurement ramp signal slope_cp When measuring the voltage of the ramp signal V slope_cp is higher than the preset reference voltage V input to the positive input terminal of the first comparator 22ref When , the output signal RST_n of the first comparator 22 is flipped from a high level to a low level, and the subsequent working principle is as described above and will not be elaborated here.

[0103] Furthermore, since the measurement circuit 20 and the logic control module 16 in the slope compensation circuit 10 can both control the slope compensation circuit 10 to charge and discharge, a selection module can be added to the slope compensation circuit 10 to select the measurement circuit 20 or the slope compensation circuit 10 to control the charging and discharging of the slope compensation circuit.

[0104] In some embodiments, Figure 5 As shown, the slope compensation circuit 10 further includes: a selection controller 17 .

[0105] The first input terminal and the second input terminal of the selection controller 17 are both used as the charge and discharge control terminals of the slope compensation circuit 10, the first input terminal of the selection controller 17 is connected to the second output terminal of the two-frequency counter 23, and the second input terminal of the selection controller 17 is connected to the output terminal of the logic control module 16; the output terminal of the selection controller 17 is connected to the control terminal of the voltage generating module 11, and the selection terminal of the selection controller 17 is used to receive a preset measurement signal tm_en, so as to determine, based on the preset measurement signal tm_en, to control the voltage generating module 11 to charge and discharge according to the first charge and discharge control signal output by the two-frequency counter 23 or the second charge and discharge control signal HS_off output by the logic control module 16.

[0106] In this embodiment, if Figure 5 As shown, when the preset measurement signal tm_en=0, the measurement circuit is not working. At this time, the second charge and discharge control signal HS_off output by the selection logic control module 16 controls the on and off of the MOS tube M4. When HS_off=0, the MOS tube M4 is turned off and the capacitor C1 is charged. When HS_off=1, the MOS tube M4 is turned on and the capacitor C1 is discharged.

[0107] When the preset measurement signal tm_en=1, the measurement circuit enters the measurement mode. At this time, the first charge and discharge control signal RST output by the divide-by-two frequency counter 23, i.e., the first inverter 231, is selected to control the on and off of the MOS tube M4. When HS_off=0, the MOS tube M4 is turned off and the capacitor C1 is charged. When HS_off=1, the MOS tube M4 is turned on and the capacitor C1 is discharged.

[0108] Furthermore, when the logic control module 16 controls the high-side power tube to be turned on, the slope compensation circuit 10 needs to provide a slope compensation voltage for the high-side power tube, and the second voltage replication module 12 needs to be turned on. When the logic control module 16 controls the high-side power tube to be turned off, the slope compensation circuit 10 does not need to provide a slope compensation voltage for the high-side power tube, and the second voltage replication module 12 needs to be turned off. Therefore, the high-side power tube and the second voltage replication module 12 can be controlled by the logic control module 16.

[0109] In some embodiments, Figure 5 As shown, the slope compensation circuit 10 further includes a second inverter 18 .

[0110] An input terminal of the second inverter 18 is connected to an output terminal of the logic control module 16 , and an output terminal of the second inverter 18 is connected to a control terminal of the second voltage replication module 12 to provide a compensation control signal HS_on for the second voltage replication module 12 .

[0111] In this embodiment, when the logic control module 16 outputs HS_off=0, HS_on=1, the high-side power tube is controlled to be turned on, the second voltage replication module 12 is turned on, and the second voltage replication module 12 provides a slope compensation voltage for the high-side power tube; when the logic control module 16 outputs HS_off=1, HS_on=0, the high-side power tube is controlled to be turned off, the second voltage replication module 12 is turned off, and the second voltage replication module 12 does not provide a slope compensation voltage for the high-side power tube.

[0112] In the slope compensation measurement circuit and method provided in the above-mentioned embodiments, when the slope compensation voltage is output to the measurement end through the measurement voltage, the wiring resistance, parasitic capacitance and parasitic inductance in the chip will not affect the frequency of the measurement clock signal. Therefore, based on the slope compensation measurement circuit, an accurate slope compensation voltage value can be obtained, and the measurement accuracy of the slope compensation voltage value is improved, so that the slope compensation voltage value can be easily adjusted.

[0113] In one possible implementation, Figure 7 A schematic diagram of the structure of a switching power supply chip provided in an embodiment of the present application is shown in FIG. Figure 7 As shown, the switching power supply chip includes: a slope compensation measurement circuit 100 and a power converter 200 ; the output end of the slope compensation circuit 10 in the slope compensation measurement circuit 100 is connected to the control end of the power converter 200 .

[0114] Furthermore, if Figure 7 As shown, the inductor current sampling output terminal and the voltage output terminal of the power converter 200 are also connected to the slope compensation circuit 10 respectively to provide the slope compensation circuit 10 with a current sampling signal CSA_out and a feedback voltage signal V FB .

[0115] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A slope compensation measurement circuit, characterized in that: The slope compensation measurement circuit comprises: a slope compensation circuit and a measurement circuit, wherein the slope compensation circuit is used to perform slope compensation on a preset power converter; The first input end of the measurement circuit is connected to the measurement end of the slope compensation circuit, the second input end of the measurement circuit receives a preset reference voltage, the control end of the measurement circuit is used to receive a preset measurement signal, so that the measurement circuit compares the preset reference voltage with the voltage of the measurement ramp signal at the measurement end to generate a measurement clock signal, and the clock signal output end of the measurement circuit is used to output the measurement clock signal, so as to calculate the slope of the voltage of the measurement ramp signal according to the frequency of the measurement clock signal and the preset reference voltage, and calculate the slope compensation voltage value of the slope compensation circuit according to the slope and the conduction time of the high-side power tube of the preset power converter.

2. The slope compensation measurement circuit according to claim 1, characterized in that: The measuring circuit comprises: a first voltage replica module, a first comparator and a divide-by-two frequency counter; The input end of the first voltage replication module serves as the first input end of the measurement circuit, and the control end of the first voltage replication module serves as the control end of the measurement circuit; The output end of the first voltage replication module is connected to the first input end of the first comparator, and the second input end of the first comparator serves as the second input end of the measurement circuit, so that the first comparator compares the preset reference voltage and the voltage of the measurement ramp signal at the measurement end to obtain a comparison result; the output end of the first comparator is connected to the input end of the divide-by-two counter, so that the divide-by-two counter performs a flip count on the comparison result to generate the measurement clock signal, and the first output end of the divide-by-two counter serves as the clock signal output end of the measurement circuit.

3. The slope compensation measurement circuit according to claim 2, characterized in that: The divide-by-two frequency counter comprises: a first inverter and a D flip-flop; The input end of the first inverter serves as the input end of the divide-by-two counter, the output end of the first inverter is connected to the clock end of the D flip-flop, and the input end of the D flip-flop is connected to the output end of the D flip-flop as the first output end of the divide-by-two counter.

4. The slope compensation measurement circuit according to claim 3, characterized in that: The first inverter outputs a first charge and discharge control signal according to the comparison result, and the output end of the first inverter is also connected to the charge and discharge control end of the slope compensation circuit to control the charge and discharge of the slope compensation circuit based on the first charge and discharge control signal.

5. The slope compensation measurement circuit according to claim 2, characterized in that: The slope compensation circuit includes: a voltage generation module, a second voltage replication module, an adder, an error amplifier, a second comparator, and a logic control module; The input end of the voltage generation module is connected to a preset power supply, the output end of the voltage generation module is connected to the input end of the second voltage replication module, and the control end of the second voltage replication module is used to receive a compensation control signal; The output end of the second voltage replication module is connected to the first input end of the adder, the second input end of the adder is used to receive the current sampling signal of the preset power converter, and the output end of the adder is connected to the positive input end of the second comparator; The positive input terminal of the error amplifier is used to receive the preset reference voltage, the negative input terminal of the error amplifier is used to receive the output voltage of the preset power converter, and the output terminal of the error amplifier is connected to the negative input terminal of the second comparator; The output end of the second comparator is connected to the input end of the logic control module, the output end of the logic control module is connected to the control end of the voltage generation module, and the control end of the voltage generation module serves as the charge and discharge control end of the slope compensation circuit; The first voltage copy module and the second voltage copy module have the same structure.

6. The slope compensation measurement circuit according to claim 5, characterized in that: The first voltage replication module includes: a first MOS tube, a second MOS tube and a resistor; The first end of the first MOS transistor serves as the input end of the first voltage replication module, the second end of the first MOS transistor is connected to the first end of the second MOS transistor, and the second end of the second MOS transistor is grounded through the resistor; The gate of the second MOS transistor serves as a control terminal of the first voltage replication module, and the connection point between the second MOS transistor and the resistor serves as an output terminal of the first voltage replication module; The size of the first MOS tube and the resistance value of the resistor are the same as the first MOS tube and the resistance value of the resistor in the second voltage replication module.

7. The slope compensation measurement circuit according to claim 5, characterized in that: The slope compensation circuit further includes: a selection controller; The first input terminal and the second input terminal of the selection controller are both used as the charge and discharge control terminals of the slope compensation circuit, the first input terminal of the selection controller is connected to the second output terminal of the two-division frequency counter, and the second input terminal of the selection controller is connected to the output terminal of the logic control module; The output end of the selection controller is connected to the control end of the voltage generating module, and the selection end of the selection controller is used to receive the preset measurement signal to determine, based on the preset measurement signal, to control the voltage generating module to charge and discharge according to the first charge and discharge control signal output by the two-division counter or the second charge and discharge control signal output by the logic control module.

8. The slope compensation measurement circuit according to claim 5, characterized in that: The slope compensation circuit further includes: a second inverter; The input end of the second inverter is connected to the output end of the logic control module, and the output end of the second inverter is connected to the control end of the second voltage replication module to provide the compensation control signal to the second voltage replication module.

9. A slope compensation measurement method, characterized in that: Applied to the slope compensation measurement circuit according to any one of claims 1 to 8, the method comprising: Controlling the measuring circuit to enter a measuring mode according to a preset measuring signal; generating a measurement clock signal according to a comparison result between the voltage of the measurement ramp signal measured by the measurement circuit and a preset reference voltage; The slope of the voltage of the measuring ramp signal is calculated according to the frequency of the measuring clock signal and the preset reference voltage, and the slope compensation voltage of the slope compensation circuit is calculated according to the slope and the on-time of the high-side power tube of the preset power converter.

10. A switching power supply chip, characterized in that: The switching power supply chip comprises: a slope compensation measurement circuit and a power converter as described in any one of claims 1 to 8; An output end of the slope compensation circuit in the slope compensation measurement circuit is connected to a control end of the power converter.

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