CN115987068A - Driving tube control circuit, control method and switching power supply - Google Patents
Driving tube control circuit, control method and switching power supply Download PDFInfo
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Abstract
The invention relates to the technical field of switching power supplies, and discloses a driving tube control circuit, a control method and a switching power supply, wherein the control circuit comprises a PWM (pulse-width modulation) driving unit, an error amplification unit and a signal processing unit, the error amplification unit outputs a first amplification signal based on the difference value of input sampling voltage and reference voltage, the signal processing unit superposes an inductance sensing signal and a compensation signal to obtain a first comparison signal, and outputs a first control signal based on the comparison result of the first comparison signal and the first amplification signal; or subtracting the compensation signal from the first amplified signal to obtain a second comparison signal, and outputting a first control signal based on the comparison result of the second comparison signal and the inductive sensing signal; when the compensation circuit is used, the compensation signal is introduced, and the compensation signal is added with the inductance sensing signal or the first amplification signal is subtracted with the compensation signal to suppress the influence of the disturbance voltage on the control voltage, so that the output of the switching power supply is stable.
Description
Technical Field
The invention relates to the technical field of switching power supplies, in particular to a driving tube control circuit, a driving tube control method and a switching power supply.
Background
In the field of power electronics, switching power supplies are often used to convert power, for example, the switching power supplies convert ac power into dc power required by a user terminal, and the dc power is usually 24V, 12V, 5V, and the like. For a switching power supply, the on-off of an input power supply part and an energy storage circuit is controlled by mainly controlling the on-off of a driving tube to adjust the output voltage. According to different control modes, the switching power supply can be divided into a voltage mode control mode and a current control mode; the voltage control mode is a single-loop control mode, namely the conduction duty ratio of the driving tube is adjusted only according to the actual output voltage; the current control mode is a double-loop control mode, namely the conduction duty ratio of the driving tube is adjusted according to the actual output voltage and the actual output current. Compared with a voltage control mode, the current control mode has better load regulation characteristic and input disturbance resistance, and is quick in dynamic response and easy to realize current limiting and overcurrent protection. However, for the switching power supply in the current control mode, when the conduction duty ratio of the driving tube is greater than 50%, if a disturbance signal exists, an error generated by the disturbance signal is gradually amplified, and finally, the output of the switching power supply is out of control and cannot be normally used.
Taking fig. 1 as an example, the principle that the output of the conventional switching power supply is unstable when the conduction duty ratio of the driving tube is greater than 50% is as follows: the method comprises the steps that the inductive current is the output current of an inductor of an energy storage circuit flowing through a switching power supply, the solid line is the inductive current without a disturbance signal, the dotted line is the inductive current with the disturbance signal, m1 is the rising slope of the inductive current, and m2 is the falling slope of the inductive current;
assuming that when the inductor current reaches the peak current, and the control voltage (the voltage indicated by the arrow in fig. 1) suddenly receives an interference signal with a time Δ t and an amplitude of + Δ V, the inductor current continuously rises within the time Δ t, assuming that the rising current amplitude is Δ I, and after the interference signal disappears, the interference signal falls with a slope of m2, after the first period ends, the disturbance current is Δ I1= Δ I + Δ I2/m 1, after the second period ends, the disturbance current Δ I2= (Δ I + Δ I m2/m 1) ("m 2/m 1"), and after the nth period ends, the disturbance current is perturbed
ΔIn=（ΔI+ΔI*m2/m1）*（m2/m1） n-1 . The calculation formula of the disturbance current can be obtained, when m2/m1 is larger than 1, namely the conduction duty ratio of the driving tube is larger than 50%, delta In is larger and larger, and therefore the system is unstable; when m2/m1 is equal to 1, the charging and discharging slopes of the inductive current are equal, namely the conduction duty ratio of the driving tube is 50%; when m2/m1 is less than 1, namely the conduction duty ratio of the driving tube is less than 50%, the disturbance current is gradually reduced, and the system tends to be stable.
Disclosure of Invention
In view of the defects of the background art, the invention provides a driving tube control circuit, a control method and a switching power supply, and aims to solve the technical problem that when the conduction duty ratio of a driving tube of the switching power supply in the existing current control mode is larger than 50%, the output of the switching power supply is more and more unstable.
In order to solve the above technical problems, in a first aspect, the present invention provides the following technical solutions: a drive tube control circuit comprises a PWM drive unit, an error amplification unit and a signal processing unit; the error amplifying unit outputs a first amplified signal based on a difference value between an input sampling voltage and a reference voltage;
the signal processing unit is configured to receive the first amplified signal and an inductive sensing signal; the signal processing unit superposes the inductance sensing signal and the compensation signal to obtain a first comparison signal, and outputs a first control signal based on a comparison result of the first comparison signal and the first amplification signal;
or the signal processing unit subtracts the compensation signal from the first amplified signal to obtain a second comparison signal, and outputs a first control signal based on a comparison result of the second comparison signal and the inductive sensing signal;
and the PWM driving unit receives the first control signal and outputs a driving signal for controlling the on-off of the driving tube based on the first control signal.
In one embodiment of the first aspect, the signal processing unit outputs a first control signal of a high level when the first amplified signal is greater than the first comparison signal, and outputs a first control signal of a low level when the first amplified signal is less than the first comparison signal;
the signal processing unit outputs a high-level first control signal when the second comparison signal is greater than the inductance sensing signal, and outputs a low-level first control signal when the second comparison signal is less than the inductance sensing signal.
In a certain implementation manner of the first aspect, the signal processing unit includes a comparing unit and a compensating unit, the compensating unit outputs the first comparing signal after superimposing the inductance sensing signal and the compensating signal, and the comparing unit compares the first comparing signal with a first amplified signal.
In a certain embodiment of the first aspect, the compensation unit comprises a current mirror unit, a compensation capacitor, a compensation resistor, and a control switch; the current mirror unit is configured to input a charging current to one end of the compensation capacitor, the other end of the charging capacitor is grounded through the compensation resistor, the control switch comprises an input end, an output end and a control end, the input end is electrically connected with one end of the compensation capacitor, the output end is electrically connected with the other end of the compensation capacitor, the control end is connected with the input end and the output end when a control signal in a first level state is input, and is disconnected when a control signal in a second level state is input; the inductive sensing signal is input to the ungrounded end of the load resistor, and one end of the compensation capacitor outputs the first comparison signal.
In one embodiment of the first aspect, the present invention further comprises a ramp generator configured to provide a ramp-shaped clock oscillation signal to the control terminal.
In one embodiment of the first aspect, the present invention further includes a voltage sampling unit, the voltage sampling unit includes a sampling input terminal and a sampling voltage output terminal, the sampling input terminal is configured to be electrically connected to the voltage output terminal of the switching power supply, the voltage sampling unit outputs a sampling voltage based on a voltage level of the voltage output terminal of the switching power supply, the sampling voltage is positively correlated with a voltage of the voltage output terminal of the switching power supply, and the sampling voltage output terminal outputs the sampling voltage.
In one embodiment of the first aspect, the voltage sampling unit includes at least two sampling resistors, all the sampling resistors are sequentially connected in series, one end of the first sampling resistor, which is not electrically connected to the sampling resistor adjacent to the first sampling resistor, is the sampling input terminal, one end of the last sampling resistor, which is not electrically connected to the sampling resistor adjacent to the last sampling resistor, is a ground terminal, which is configured to be grounded, and one of electrical nodes of the voltage sampling unit between the sampling input terminal and the ground terminal is the sampling voltage output terminal.
In a certain embodiment of the first aspect, the present invention further includes a current sampling unit, configured to collect an inductor current of an energy storage current flowing through the switching power supply, and output an inductor sense signal, where the inductor sense signal is positively correlated with the inductor current.
In a second aspect, the present invention further provides a driving tube control method for controlling the on/off of a driving tube of a switching power supply, including the following steps:
s1: collecting the output voltage of the switching power supply and outputting a sampling voltage;
s2: amplifying the difference value of the sampling voltage and the reference voltage, and outputting a first amplified signal;
s3: superposing the inductance sensing signal and the compensation signal to obtain a first comparison signal, comparing the first amplification signal with the first comparison signal, and outputting a first control signal based on a comparison result;
or the first amplified signal is subtracted by the compensation signal to obtain a second comparison signal, the second comparison signal is compared with the inductive induction signal, and a first control signal is output according to the comparison result;
s4: and inputting the first control signal into the PWM driving unit, and controlling the on-off of the driving tube of the closing unit through the PWM driving unit.
In a third aspect, the invention further provides a switching power supply, which includes the above-mentioned driving tube control circuit.
Compared with the prior art, the invention has the beneficial effects that: the invention inhibits the influence of the disturbance voltage on the control voltage by introducing the compensation signal and adding the compensation signal and the inductance sensing signal or subtracting the first amplification signal and the compensation signal, thereby stabilizing the output of the switching power supply.
Drawings
FIG. 1 is a schematic diagram illustrating the variation of current flowing through the inductor of the tank circuit of the switching power supply in the presence of a disturbance signal;
FIG. 2 is a first structural diagram of the present invention;
FIG. 3 is a waveform diagram of a second comparison signal corresponding to the first amplified signal minus the compensation signal;
FIG. 4 is a second schematic construction of the present invention;
FIG. 5 is a circuit diagram of a compensation unit according to the present invention;
FIG. 6 is a schematic view of a third embodiment of the present invention;
FIG. 7 is a schematic diagram of the structure shown in FIG. 6 applied to a switching power supply;
FIG. 8 is a flow chart of a drive tube control method of the present invention;
FIG. 9 is a simulation diagram of the compensation amount when the inductive sense signal is 0 according to the present invention;
FIG. 10 is a simulation diagram of the compensation amount of the inductive signal in normal state according to the present invention;
fig. 11 is a simulation diagram of the switching power supply when the offset amount is 110mV.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.
A switching power supply, a power conversion device, is generally used for converting alternating current into direct current, and mainly comprises a driving tube, an energy storage circuit and a driving tube control circuit, wherein the energy storage circuit comprises an inductor, and the driving tube control circuit determines whether to charge the energy storage circuit by controlling the on-off of the driving tube. After the duty ratio of the driving tube of the conventional switching power supply is greater than 50%, if a disturbance signal exists to change the control voltage of the conduction duty ratio of the driving tube, the output of the switching power supply is unstable, and the normal operation of the switching power supply is influenced.
For the above reasons, as shown in fig. 2, the present invention provides a driving tube control circuit, which includes a PWM driving unit 3, an error amplifying unit 1 and a signal processing unit 2; the error amplifying unit 1 outputs a first amplified signal VCOMP based on a difference between an input sampling voltage Vc and a reference voltage Vref; wherein the first amplified signal VCOMP is the control voltage;
the signal processing unit 2 is configured to receive the first amplified signal VCOMP and the inductance-induced signal CS; the signal processing unit 2 superimposes the inductance sensing signal CS and the compensation signal to obtain a first comparison signal, and outputs a first control signal based on a comparison result of the first comparison signal and the first amplification signal VCOMP;
or the signal processing unit 2 subtracts the compensation signal from the first amplified signal VCOMP to obtain a second comparison signal, and outputs the first control signal based on the comparison result between the second comparison signal and the inductance sensing signal CS;
the PWM driving unit 3 receives the first control signal and outputs a driving signal for controlling the on-off of the driving tube based on the first control signal.
Specifically, the signal processing unit 2 outputs a first control signal of a high level when the first amplified signal VCOMP is greater than the first comparison signal, and outputs a first control signal of a low level when the first amplified signal VCOMP is less than the first comparison signal;
the signal processing unit 2 outputs a first control signal of a high level when the second comparison signal is greater than the inductance sensing signal CS, and outputs a first control signal of a low level when the second comparison signal is less than the inductance sensing signal CS.
The process of controlling the on-off of the driving tube by the PWM driving unit 3 is as follows: when the first control signal is at a high level, the PWM driving unit 3 controls the conduction of a driving tube for charging the energy storage circuit and controls the disconnection of the driving tube for discharging the energy storage circuit; when the first control signal is at a low level, the PWM driving unit 3 controls the driving tube for charging the energy storage circuit to be turned off, and controls the driving tube for discharging the energy storage circuit to be turned on.
Specifically, in the present embodiment, the compensation signal is a periodic ramp waveform, and if the inductance-induced signal CS is fixed, the first comparison signal is a periodic ramp waveform after the inductance-induced signal CS and the compensation signal are superimposed. When the first amplifying signal VCOMP is increased due to the existence of the disturbance signal, the first control signal output by the signal processing unit 2 can gradually return to normal through the compensation of the compensation signal, thereby ensuring that the PWM driving unit 3 normally controls the on/off of the driving tube in the switching power supply. In addition, when the compensation signal is subtracted from the first amplified signal VCOMP, the obtained second comparison signal is also ramp-shaped, and the specific diagram is shown in fig. 3, and the analysis process of fig. 3 is as follows:
wherein the second comparison signal is a sawtooth wave with a falling slope of m3, and if the disturbance current is delta I, the inductor charging slope is m1, and the inductor discharging slope is m2, then
m1 Δ t = I1, m3 Δ t = I2, and I 1 +I 2 = Δ I, Δ t = Δ I/(m 3+ m 1), and therefore
ΔI 1 =m2*Δt-I 2 =m2*ΔI/(m3+m1)-m3*ΔI/(m3+m1)= ΔI*(m2-m3)/(m1+m3)
ΔI 2 =m2*Δt1-I 2_1 =ΔI1*(m2-m3)/(m1+m3)= ΔI*((m2-m3)/(m1+m3)) 2
ΔI n =ΔI*((m2-m3)/(m1+m3)) n 。
From the calculation formula of Δ In, as long as (m 2-m 3)/(m 1+ m 3) is less than 1 (the condition is a stable condition), the switching power supply can still be stable after receiving disturbance.
From volt-second law, m1 × D = m2 × (1-D), bringing into stable conditions can be obtained
(m 2-m 3) < m2 (1-D)/D + m3, and m3/m2> (1-1/2D) can be obtained by simplification. Therefore, after the compensation signal is added, when D is less than 0.5, m3/m2>0> (1-1/2D), the switching power supply can be kept stable, and when D is more than 0.5, and m3/m2 is more than 0.5, the switching power supply can also be kept stable.
Specifically, as shown in fig. 4, in the present embodiment, the signal processing unit 2 includes a comparing unit COMP and a compensating unit 20, the compensating unit 20 outputs a first comparing signal after superimposing the inductance sensing signal CS and the compensating signal, and the comparing unit COMP compares the first comparing signal with the first amplified signal.
The circuit diagram of the compensation unit 20 is shown in fig. 5, and includes a current mirror unit, a compensation capacitor C1, a compensation resistor R1, and a control switch N1; the current mirror unit comprises a PMOS (P-channel metal oxide semiconductor) tube P1 and a PMOS tube P2, the current mirror unit is configured to input charging current to one end of a compensation capacitor C1, the other end of the charging capacitor C1 is grounded through a compensation resistor R1, the control switch N1 comprises an input end, an output end and a control end, the input end is electrically connected with one end of the compensation capacitor C1, the output end is electrically connected with the other end of the compensation capacitor C1, the input end and the output end are conducted when the control end inputs a control signal in a first level state, and the input end and the output end are disconnected when the control signal in a second level state is input; an inductance sensing signal CS is input to one ungrounded end of a load resistor R1, and one end of a compensation capacitor C1 outputs a first comparison signal CS _ Slop; the first level state is a high level state, the second level state is a low level state, and the control switch N1 is an NMOS tube.
For the circuit shown in fig. 5, in order to ensure that the compensation signal is ramp-shaped, in fig. 7, the invention further comprises a ramp generator 6, the ramp generator 6 providing a clock oscillation signal Vramp of sawtooth-shaped to the control terminal of the control switch N1. In practical use, the control switch N1 is turned on at the highest point of the clock oscillation signal Vramp or in a time period having a certain interval with the highest point by controlling the highest voltage value of the clock oscillation signal Vramp in a period, so that the voltage of the compensation capacitor C1 can be reset, thereby providing a periodic compensation signal.
In the circuit shown in fig. 5, the current mirror unit outputs the charging current after scaling the current I1, and assuming that the gate lengths of the PMOS transistor P1 and the PMOS transistor P2 are the same, the gate width ratio of the PMOS transistor P1 to the PMOS transistor P2 is 1: n, the charging current is I1 × N, so the magnitude of the charging current can be changed by setting parameters of the PMOS transistor P1 and the PMOS transistor P2, the voltage change rate of the compensation capacitor C1 can be changed by changing the magnitude of the charging current, and assuming that the charging current is always input to the compensation capacitor C1 within the time t, the voltage of the compensation capacitor C1 after the time t is N × I1 × t/C, and t is the on-time of the driving transistor of the switching power supply within the period, at this time, the compensation amount Δ m = N × I1 × t/C. Therefore, in addition to setting the proportion of the proportional change of the current mirror unit, the compensation amount Δ m can be adjusted by selecting the compensation capacitor C1 with different capacitance values.
As shown in fig. 6, in this embodiment, the present invention further includes a voltage sampling unit 4, where the voltage sampling unit 4 includes a sampling input end and a sampling voltage output end, the sampling input end is configured to be electrically connected to the voltage output end of the switching power supply, the voltage sampling unit 5 outputs a sampling voltage VC based on the voltage of the voltage output end of the switching power supply, the sampling voltage is positively correlated to the voltage of the voltage output end of the switching power supply, and the sampling voltage output end outputs the sampling voltage VC.
In fig. 6, the present invention further includes a current sampling unit 5, where the current sampling unit 5 is configured to collect an inductive current of the energy storage current flowing through the switching power supply, and output an inductive sensing signal CS, where the inductive sensing signal CS is positively correlated with the inductive current.
In addition, as shown in fig. 8, the present invention also provides a driving tube control method, including the steps of: s1: collecting the output voltage of the switching power supply and outputting a sampling voltage;
s2: amplifying the difference value of the sampling voltage and the reference voltage, and outputting a first amplified signal;
s3: superposing the inductance sensing signal and the compensation signal to obtain a first comparison signal, comparing the first amplified signal with the first comparison signal, and outputting a first control signal based on the comparison result;
or the first amplified signal is subtracted by the compensation signal to obtain a second comparison signal, the second comparison signal is compared with the inductive induction signal, and a first control signal is output according to the comparison result;
s4: and inputting the first control signal into the PWM driving unit, and controlling the on-off of the driving tube of the closing unit through the PWM driving unit.
Wherein the compensation signal is saw-tooth wave shaped.
In addition, in this embodiment, the present invention further provides a switching power supply, where the switching power supply includes the above-mentioned driving transistor control circuit.
Specifically, in fig. 7, the inductor L1 is an energy storage circuit, the PMOS transistor P3 is a driving transistor for controlling whether the power supply Vi charges the inductor L1, and the NMOS transistor N2 is a driving transistor for controlling whether the inductor L1 discharges. The voltage sampling unit 4 is composed of a resistor R3 and a resistor R4, one end of the resistor R3, which is not electrically connected with the resistor R4, is a sampling end, one end of the resistor R3, which is electrically connected with the resistor R4, is a sampling voltage output end, the error discharge unit 1 is an error amplifier Eamp, and both the inductance sensing signal CS and the clock oscillation signal Vramp are input into the compensation unit 20.
For the switching power supply shown in fig. 7, the error amplification unit 1 implements voltage loop feedback control, and the signal processing unit 2 is used to implement current loop feedback control.
The circuit is designed so that the compensation amount Δ m is 110mV when the period of the clock oscillation signal Vramp is 20 us. The circuit is simulated, first with the compensation Δ m, from fig. 9, it can be seen that the actual compensation Δ m has a value of about 110mV when the inductance-induced signal CS is forced to 0V, while from fig. 10, it can be seen that the compensation Δ m is about 110mV when the inductance-induced signal CS is not forced to 0.
When the compensation amount Δ m is 110mV, the output duty ratio of the switching power supply is made to be larger than 94%, and then the switching power supply is simulated, and a simulation result is schematically shown in fig. 11, which can be obtained from fig. 11, and when the compensation amount Δ m is 110mV and the driving output duty ratio is larger than 94%, the inductor current flowing through the inductor of the switching power supply can still be kept stable.
In conclusion, the invention has the following advantages:
firstly, the structure is simple, the compensation unit 20 superposes the inductive sensing signal CS and the compensation signal to generate a sawtooth-wave-shaped first comparison signal CS _ Slop, and the comparison unit COMP compares the first comparison signal CS _ Slop and the first amplification signal VOMP to realize compensation control and reduce the output influence of a disturbance signal on the switching power supply;
secondly, the driving output duty ratio range of the switching power supply of the invention is wide, and as can be obtained from fig. 11, when the driving output duty ratio exceeds 90%, the output of the switching power supply still keeps stable;
finally, the compensation quantity in each period can be adjusted by setting the current conversion proportion of the current mirror unit of the driving tube control circuit and the size of the compensation capacitor C1, so that the required compensation quantity can be provided for the switching power supplies with different output duty ratios, and the application range is wide.
In light of the foregoing, it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (10)
1. A drive tube control circuit comprises a PWM drive unit, and is characterized by also comprising an error amplification unit and a signal processing unit; the error amplifying unit outputs a first amplified signal based on a difference value between an input sampling voltage and a reference voltage;
the signal processing unit is configured to receive the first amplified signal and an inductive sensing signal; the signal processing unit superposes the inductance sensing signal and the compensation signal to obtain a first comparison signal, and outputs a first control signal based on a comparison result of the first comparison signal and the first amplification signal;
or the signal processing unit subtracts the compensation signal from the first amplified signal to obtain a second comparison signal, and outputs a first control signal based on a comparison result of the second comparison signal and the inductive sensing signal;
and the PWM driving unit receives the first control signal and outputs a driving signal for controlling the on-off of the driving tube based on the first control signal.
2. The driving transistor control circuit according to claim 1, wherein the signal processing unit outputs a first control signal of a high level when the first amplified signal is greater than the first comparison signal, and outputs a first control signal of a low level when the first amplified signal is less than the first comparison signal;
the signal processing unit outputs a high-level first control signal when the second comparison signal is greater than the inductance sensing signal, and outputs a low-level first control signal when the second comparison signal is less than the inductance sensing signal.
3. The driving tube control circuit according to claim 1, wherein the signal processing unit comprises a comparing unit and a compensating unit, the compensating unit outputs the first comparing signal after superimposing the inductance sensing signal and the compensating signal, and the comparing unit compares the first comparing signal with a first amplified signal.
4. The driving tube control circuit according to claim 3, wherein the compensation unit comprises a current mirror unit, a compensation capacitor, a compensation resistor and a control switch; the current mirror unit is configured to input a charging current to one end of the compensation capacitor, the other end of the charging capacitor is grounded through the compensation resistor, the control switch comprises an input end, an output end and a control end, the input end is electrically connected with one end of the compensation capacitor, the output end is electrically connected with the other end of the compensation capacitor, the control end is connected with the input end and the output end when a control signal in a first level state is input, and is disconnected when a control signal in a second level state is input; the inductive sensing signal is input to the ungrounded end of the load resistor, and one end of the compensation capacitor outputs the first comparison signal.
5. The drive tube control circuit of claim 4, further comprising a ramp generator configured to provide a ramp-like clock oscillation signal to the control terminal.
6. The driver tube control circuit according to any of claims 1-5, further comprising a voltage sampling unit, wherein the voltage sampling unit comprises a sampling input terminal and a sampling voltage output terminal, the sampling input terminal is configured to be electrically connected to the voltage output terminal of the switching power supply, the voltage sampling unit outputs a sampling voltage based on a voltage magnitude of the voltage output terminal of the switching power supply, the sampling voltage is positively correlated to a voltage of the voltage output terminal of the switching power supply, and the sampling voltage output terminal outputs the sampling voltage.
7. The driving tube control circuit according to claim 6, wherein the voltage sampling unit includes at least two sampling resistors, all the sampling resistors are sequentially connected in series, one end of the first sampling resistor, which is not electrically connected to the sampling resistor adjacent to the first sampling resistor, is the sampling input terminal, one end of the last sampling resistor, which is not electrically connected to the sampling resistor adjacent to the last sampling resistor, is a ground terminal, which is configured to be grounded, and one of electrical nodes of the voltage sampling unit between the sampling input terminal and the ground terminal is the sampling voltage output terminal.
8. The driving tube control circuit according to any one of claims 1 to 5, further comprising a current sampling unit, wherein the current sampling unit is configured to collect a magnitude of an inductive current flowing through an energy storage circuit of the switching power supply and output an inductive signal, and the inductive signal is positively correlated to the inductive current.
9. A driving tube control method is used for controlling the on-off of a driving tube of a switching power supply and is characterized by comprising the following steps:
s1: collecting the output voltage of the switching power supply and outputting a sampling voltage;
s2: amplifying the difference value of the sampling voltage and the reference voltage, and outputting a first amplified signal;
s3: superposing the inductance sensing signal and the compensation signal to obtain a first comparison signal, comparing the first amplified signal with the first comparison signal, and outputting a first control signal based on the comparison result;
or the first amplified signal is subtracted by the compensation signal to obtain a second comparison signal, the second comparison signal is compared with the inductive induction signal, and a first control signal is output according to the comparison result;
s4: and inputting the first control signal into the PWM driving unit, and controlling the on-off of the driving tube of the switching unit through the PWM driving unit.
10. A switching power supply comprising a drive transistor control circuit as claimed in any one of claims 1 to 8.
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| CN202310256980.0A Pending CN115987068A (en) | 2023-03-17 | 2023-03-17 | Driving tube control circuit, control method and switching power supply |
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| CN (1) | CN115987068A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104901534A (en) * | 2015-05-19 | 2015-09-09 | 深圳创维－Rgb电子有限公司 | Slope compensating circuit and DC-DC conversion device |
| CN108696105A (en) * | 2018-07-09 | 2018-10-23 | 杰华特微电子（张家港）有限公司 | Switching power source control circuit and Switching Power Supply |
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2023
- 2023-03-17 CN CN202310256980.0A patent/CN115987068A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104901534A (en) * | 2015-05-19 | 2015-09-09 | 深圳创维－Rgb电子有限公司 | Slope compensating circuit and DC-DC conversion device |
| CN108696105A (en) * | 2018-07-09 | 2018-10-23 | 杰华特微电子（张家港）有限公司 | Switching power source control circuit and Switching Power Supply |
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Application publication date: 20230418 |