CN111629496B - Charge pump control circuit and driving power supply - Google Patents
Charge pump control circuit and driving power supply Download PDFInfo
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- CN111629496B CN111629496B CN202010538156.0A CN202010538156A CN111629496B CN 111629496 B CN111629496 B CN 111629496B CN 202010538156 A CN202010538156 A CN 202010538156A CN 111629496 B CN111629496 B CN 111629496B
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
- H05B47/10—Controlling the light source
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Abstract
The application discloses a charge pump control circuit, which comprises a control switch and a control circuit; the control switch is connected in parallel with two ends of the charge pump circuit, and the control end of the control switch is connected with the output end of the control circuit; and the control circuit is used for generating a feedback signal according to the voltage at two ends of the bus capacitor, generating a triangular wave signal according to a driving signal of a switching tube in the resonance main circuit, comparing the feedback signal with the triangular wave signal, and controlling the control switch to be switched on when the triangular wave signal is greater than the feedback signal so as to short circuit the charge pump circuit. The switching tube comprises an upper switching tube and a lower switching tube which are in a bridge structure; the magnitude of the feedback signal is in negative correlation with the magnitude of the voltage at two ends of the bus capacitor, and the conducting time of the control switch is in negative correlation with the magnitude of the feedback signal. The circuit can stabilize the voltage of the bus capacitor at a certain voltage value. The application also discloses a driving power supply which has the technical effect.
Description
Technical Field
The application relates to the technical field of LED lamps, in particular to a charge pump control circuit; and also relates to a driving power supply.
Background
In the technical field of LED lamps, a driving power supply with high power density, high efficiency and low cost is more competitive. Usually, the driving power source selects a resonant circuit to achieve the objectives of high power density and high efficiency. The resonant circuit can realize zero voltage switching-on of two or more switching tubes on the primary side and zero current switching-off of the secondary side rectifier diode, can reduce the switching loss of a power supply, and improves the efficiency and the power density of the power converter. Meanwhile, in order to improve the power factor, a first-stage active PFC circuit, i.e., a power factor correction circuit, is often added at a front stage of the resonant circuit. However, this results in a complex and costly circuit.
Therefore, in the prior art, a charge pump circuit replaces a PFC circuit, so that a single-stage resonant circuit meets the requirement of power factors. However, the resonant circuit having the charge pump has the following problems: when the circuit is under the working condition that the amplitude of the input voltage is changed within a certain range, when the amplitude of the input voltage is increased and the energy required by the resonance main circuit is unchanged, the voltage on the bus capacitor is immediately increased; or, when the output power of the resonant main circuit changes within a certain range (i.e. the power required by the resonant main circuit changes within a certain range), the output power decreases and the input voltage does not change, and the voltage on the bus capacitor increases immediately. If the voltage on the bus capacitor is at a higher amplitude level, the related devices of the later stage resonant main circuit need to bear higher voltage stress. Therefore, when designing the circuit, these devices of the resonant main circuit need to select the withstand voltage performance according to the bus capacitor voltage of the highest magnitude. The devices with high voltage resistance are expensive, and for circuits which work under low-amplitude bus capacitor voltage for a long time and occasionally work under high-amplitude bus capacitor voltage, the devices with high voltage resistance are selected to be too wasteful and must be selected, otherwise, the devices can be damaged due to voltage resistance under the high-amplitude bus capacitor voltage.
In view of this, it is a technical problem to be solved by those skilled in the art how to stabilize the voltage of the bus capacitor at a certain voltage value to avoid the voltage stress on the devices of the subsequent circuit due to the overhigh voltage of the bus capacitor.
Disclosure of Invention
The application aims to provide a charge pump control circuit, which can stabilize the voltage of a bus capacitor at a certain voltage value, and avoid voltage pressure on devices of a post-stage circuit caused by overhigh voltage of the bus capacitor; another object of the present application is to provide a driving power supply having the above technical effects as well.
In order to solve the above technical problem, the present application provides a charge pump control circuit, including:
a control switch and a control circuit; the control switch is connected in parallel with two ends of the charge pump circuit, and the control end of the control switch is connected with the output end of the control circuit;
the control circuit is used for generating a feedback signal according to the voltage at two ends of the bus capacitor, generating a triangular wave signal according to a driving signal of a switching tube in the resonant main circuit, comparing the feedback signal with the triangular wave signal, controlling the control switch to be switched on when the triangular wave signal is greater than the feedback signal so as to short circuit the charge pump circuit, and controlling the control switch to be switched off when the triangular wave signal is not greater than the feedback signal;
the switching tube comprises an upper switching tube and a lower switching tube which are in a bridge structure; the magnitude of the feedback signal is in negative correlation with the magnitude of the voltage at two ends of the bus capacitor, and the conduction time of the control switch is in negative correlation with the magnitude of the feedback signal.
Optionally, the control circuit includes:
the circuit comprises a comparator, a triangular wave generating circuit and a feedback circuit; wherein the driving signal is a driving signal of the lower switching tube;
the input end of the triangular wave generating circuit inputs the driving signal, and the output end of the triangular wave generating circuit is connected with the in-phase end of the comparator and used for generating a triangular wave signal according to the driving signal and outputting the triangular wave signal to the in-phase end of the comparator; the starting time of the triangular wave signal is the turn-off time of the lower switching tube; the signal period of the triangular wave signal is the signal period of the driving signal;
the input end of the feedback circuit inputs a reference signal and voltages at two ends of the bus capacitor, and the output end of the feedback circuit is connected with the negative phase input end of the comparator and is used for generating the feedback signal according to the reference signal and the voltages at two ends of the bus capacitor and outputting the feedback signal to the negative phase input end of the comparator;
the output end of the comparator is used as the output end of the control circuit, is connected with the control switch, and is used for generating the control signal according to the triangular wave signal and the feedback signal and outputting the control signal to the control switch.
Optionally, the triangle wave generating circuit includes:
the controllable switch, a first voltage source, a first resistor, a second resistor, a third resistor, a first capacitor and a second capacitor;
the first voltage source is connected with a first end of the first resistor and a second end of the controllable switch, a second end of the first resistor is connected with a first end of the controllable switch and a first end of the second resistor, a second end of the second resistor is connected with a first end of the first capacitor, a second end of the first capacitor is connected with a driving signal of the switch tube of the resonance main circuit, a third end of the controllable switch is connected with a first common end of the third resistor and the second capacitor after being connected in parallel and serves as an output end of the triangular wave generation circuit, and a second common end of the third resistor and the second capacitor after being connected in parallel is grounded.
Optionally, the controllable switch is a PNP type triode; the base electrode of the PNP type triode is the first end of the switch tube, the emitter electrode of the PNP type triode is the second end of the switch tube, and the collector electrode of the PNP type triode is the third end of the switch tube.
Optionally, the feedback circuit includes:
the operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor and a third capacitor; the fourth resistor is connected with the fifth resistor in series at two ends of the bus capacitor, the inverting input end of the operational amplifier is connected with one end of the fourth resistor connected with the fifth resistor, the same-phase end of the operational amplifier inputs a reference signal, the output end of the operational amplifier serves as the output end of the feedback circuit, the output end of the operational amplifier is connected with the third capacitor in series and connected with the negative-phase input end of the operational amplifier behind the sixth resistor, the other end of the fourth resistor is connected with the voltages at two ends of the bus capacitor, and the other end of the fifth resistor is grounded.
Optionally, the feedback circuit includes:
the three-terminal voltage regulator tube, the second voltage source, the seventh resistor, the eighth resistor, the ninth resistor, the tenth resistor and the fourth capacitor;
the cathode of the three-terminal voltage-stabilizing tube is used as the output end of the feedback circuit, the cathode of the three-terminal voltage-stabilizing tube is connected with the tenth resistor in series and then is connected with the second voltage source, the anode of the three-terminal voltage-stabilizing tube is connected with one end of the eighth resistor and is grounded, the other end of the eighth resistor is connected with one end of the seventh resistor, the other end of the seventh resistor is connected with the voltage at two ends of the bus capacitor, the reference end of the three-terminal voltage-stabilizing tube is connected with the fourth capacitor and the ninth resistor in series and then is connected with the cathode of the three-terminal voltage-stabilizing tube, the seventh resistor and the eighth resistor are connected with two ends of the bus capacitor in series and the reference end of the three-terminal voltage-stabilizing tube is connected between the seventh resistor and the eighth resistor.
Optionally, the control switch is an MOS transistor.
In order to solve the above technical problem, the present application further provides a driving power supply, including:
rectifier bridge, bus capacitor, resonance main circuit, charge pump circuit, resonance control circuit and charge pump control circuit as described above.
Optionally, when a control switch in the charge pump control circuit is an MOS transistor, the charge pump circuit and the MOS transistor share a parasitic diode of the MOS transistor.
The charge pump control circuit that this application provided includes: a control switch and a control circuit; the control switch is connected in parallel with two ends of the charge pump circuit, and the control end of the control switch is connected with the output end of the control circuit; the control circuit is used for generating a feedback signal according to the voltage at two ends of the bus capacitor, generating a triangular wave signal according to a driving signal of a switching tube in the resonant main circuit, comparing the feedback signal with the triangular wave signal, controlling the control switch to be switched on when the triangular wave signal is greater than the feedback signal so as to short circuit the charge pump circuit, and controlling the control switch to be switched off when the triangular wave signal is not greater than the feedback signal; the switching tube comprises an upper switching tube and a lower switching tube which are in a bridge structure; the magnitude of the feedback signal is in negative correlation with the magnitude of the voltage at two ends of the bus capacitor, and the conduction time of the control switch is in negative correlation with the magnitude of the feedback signal.
Therefore, the charge pump control circuit provided by the application comprises the control switch and the control circuit, wherein the control switch is connected to two ends of the charge pump circuit in parallel, and the control circuit is used for controlling the on-off state of the control switch. Specifically, the control circuit is used for controlling the switch state of the control switch according to a feedback signal related to the voltage at two ends of the bus capacitor and a driving signal of a switch tube in the resonance main circuit, so that the control switch is conducted within the time of passing a forward resonance current in the resonance main circuit, the charge pump circuit is short-circuited, and the bus capacitor releases electric energy to a post-stage circuit, because the feedback signal is in negative correlation with the voltage at the two ends of the bus capacitor, and the conduction time of the control switch is in negative correlation with the magnitude of the feedback signal, therefore, the larger the voltage at the two ends of the bus capacitor is, the smaller the feedback signal is, the longer the time for controlling the switch to be conducted is, the more electric energy can be released to the backward stage circuit by the bus capacitor, and then the voltage at the two ends of the bus capacitor is reduced, the voltage at the two ends of the bus capacitor is stabilized at a certain voltage value, and the voltage pressure on devices of a later-stage circuit caused by overhigh voltage of the bus capacitor is avoided.
The driving power supply provided by the application also has the technical effects.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the prior art and the embodiments are briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic diagram of a conventional driving power supply;
fig. 2 is a schematic diagram of a charge pump control circuit according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram of a control circuit according to an embodiment of the present disclosure;
FIG. 4 is a waveform diagram provided by an embodiment of the present application;
fig. 5 is a schematic diagram of a triangle wave generating circuit according to an embodiment of the present disclosure;
fig. 6 is a schematic diagram of a feedback circuit according to an embodiment of the present disclosure;
FIG. 7 is a schematic diagram of another feedback circuit provided in an embodiment of the present application;
fig. 8 is a schematic diagram of a resonance control circuit according to an embodiment of the present disclosure.
Detailed Description
The core of the application is to provide a charge pump control circuit, which can stabilize the voltage of a bus capacitor at a certain voltage value, and avoid voltage pressure on devices of a later-stage circuit caused by overhigh voltage of the bus capacitor; another core of the present application is to provide a driving power supply, which also has the above technical effects.
In order to make the objects, 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 with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, a conventional driving power supply includes a rectifier bridge, a bus capacitor, a resonant main circuit, a resonant control circuit, and a charge pump circuit. The resonance control circuit is responsible for collecting output parameters of the resonance main circuit, such as output voltage or output current, and controlling the working states of a switch tube Q1 and a switch tube Q2 in the resonance main circuit according to the output parameters, so that the resonance main circuit outputs stable output voltage or output current. Resonant current Ir is generated by resonant operation of a resonant inductor L, a resonant capacitor C3 and a transformer T in the resonant main circuit, and a switching tube Q1 and a switching tube Q2 in a bridge structure are conducted in a complementary mode or conducted in a staggered mode with the same duty ratio. When the resonant main circuit passes through the forward resonant current Ir, as indicated by the direction of Ir in fig. 1, the charge pump circuit shunts the forward resonant current Ir, and most of the time in the period overlaps with the conduction time of the switching tube Q1; when the negative resonant current Ir passes through the main resonant circuit, the charge pump does not process the negative resonant current Ir, but only provides a current loop (through the diode D) in a direction opposite to the direction of Ir indicated in fig. 1, and most of the time during this period overlaps with the on-time of the switching tube Q2.
In the resonant main circuit, the switching tube Q1 and the switching tube Q2 are in a bridge structure, and the application defines two switching tubes similar to the bridge structure as an upper switching tube and a lower switching tube, the switching tube connected with a high level of direct current voltage is referred to as an upper switching tube, Q1 in fig. 1 is an upper switching tube, the switching tube connected with a low level of direct current voltage is referred to as a lower switching tube, and Q2 in fig. 1 is a lower switching tube.
The voltage VC1 (namely the voltage at two ends of the bus capacitor C1) on the bus capacitor of the main resonant circuit and the bus capacitor C1 are used for storing intermediate energy, the energy of the input power supply is stored on the bus capacitor, and the later main resonant circuit picks up the energy from the bus capacitor. When the circuit is under the working condition that the amplitude of the input voltage Vin can be changed within a certain range, when the amplitude of the input voltage Vin is increased and the energy required by the resonant main circuit is unchanged, the voltage VC1 on the bus capacitor is increased immediately. Or, under the working condition that the output power of the resonant main circuit changes within a certain range (i.e. the power required by the resonant main circuit changes within a certain range), when the output power decreases and the input voltage Vin does not change, the voltage VC1 on the bus capacitor increases immediately. If the voltage VC1 on the bus capacitor is at a higher amplitude level, the devices (the switch Q1, the switch Q2 and the resonant capacitor C3) related to the rear-stage resonant main circuit need to withstand higher voltage stress. Therefore, the present application provides a charge pump control circuit, which can effectively solve the technical defects.
Referring to fig. 2, fig. 2 is a schematic diagram of a charge pump control circuit according to an embodiment of the present disclosure, referring to fig. 2, the charge pump control circuit mainly includes:
control switch S1 and control circuit 10; the control switch S1 is connected in parallel to two ends of the charge pump circuit, and the control end of the control switch S1 is connected to the output end of the control circuit 10, and the control switch S1 is controlled by the control circuit 10.
And the control circuit 10 is used for generating a feedback signal according to the voltage at two ends of the bus capacitor, generating a triangular wave signal according to a driving signal of a switching tube in the resonance main circuit, generating a control signal according to the feedback signal and the triangular wave signal, outputting the control signal to the control switch S1 and controlling the control switch S1. Specifically, the feedback signal is compared with the triangular wave signal, and when the triangular wave signal is greater than the feedback signal, the control switch S1 is controlled to be turned on, so as to short-circuit the charge pump circuit. When the triangular wave signal is not greater than the feedback signal, the control switch S1 is controlled to be switched off.
The feedback signal is generated according to the voltage at two ends of the bus capacitor, preferably, the bus voltage is compared with a preset value of the bus voltage, the bus voltage is input to a proportional-integral circuit of the operational amplifier, and the feedback signal is output through the circuit. Thus, the magnitude of the feedback signal reflects the difference between the bus voltage and the preset value.
Since the triangular wave signal is generated according to the driving signal of the switching tube of the resonant main circuit, that is, the period phase of the triangular wave signal is the same as that of the switching tube Q1 or Q2, the control signal generated by the triangular wave signal controls the switch S1 to be turned on for a certain time in the switching period of the switching tube Q1 or Q2, and is turned off for the rest of the switching period of the switching tube Q1 or Q2. And then the on-time of the control switch is changed through the magnitude of the feedback signal, so that the energy released by the bus capacitor to the rear-stage resonant circuit can be adjusted in a longer time period (the time period is far greater than the switching period of the switching tube Q1 or Q2), and the voltage on the bus capacitor is stabilized at a set value. Specifically, the magnitude of the feedback signal is in negative correlation with the magnitude of the voltage at two ends of the bus capacitor, and the control signal obtained by comparing the feedback signal with the triangular wave makes the on-time of the control switch and the magnitude of the feedback signal in negative correlation, so that the on-time of the control switch is in positive correlation with the voltage at two ends of the bus capacitor, when the voltage of the bus capacitor is higher than a preset value, the feedback signal is reduced, the on-time of the control switch is increased, and the bus capacitor releases more energy to the resonant main circuit, so that the voltage of the bus capacitor can be adjusted to be reduced to the preset value; similarly, when the voltage of the bus capacitor is lower than the preset value, the feedback signal is increased, the conduction time of the control switch is reduced, and the energy release of the bus capacitor to the resonance main circuit is reduced, so that the voltage of the bus capacitor can be adjusted to be increased to the preset value.
The on/off of the control switch S1 is repeated in cycles with the switching cycle of the switching tube Q1 or Q2. That is, the control switch S1 will turn on and off once in one switching cycle of the switch Q1 or Q2. The change of the magnitude of the feedback signal is not completed in a switching period, but is adjusted in a longer time period, namely the energy release and storage change of the bus capacitor is completed in the longer time period. And one of the two time periods is the switching period of the switching tube Q1 or Q2, and the other is the regulating time period of the bus capacitor, and the latter is far larger than the former.
The present application connects the control switch S1 in parallel across the charge pump circuit to short the charge pump circuit when the control switch S1 is turned on. In a specific embodiment, the control switch S1 is a MOS transistor.
Referring to fig. 3, in a specific embodiment, the control circuit 10 includes: a comparator U1, a triangular wave generation circuit 101, and a feedback circuit 102; wherein, the driving signal is the driving signal of the lower switch tube Q2; the input end of the triangular wave generating circuit 101 inputs a driving signal, and the output end of the triangular wave generating circuit 101 is connected with the in-phase end of the comparator U1 and used for generating a triangular wave signal according to the driving signal and outputting the triangular wave signal to the in-phase end of the comparator U1; the starting time of the triangular wave signal is the turn-off time of the lower switching tube Q2; the signal period of the triangular wave signal is the signal period of the driving signal; the voltage X1 at two ends of the bus capacitor at the input end of the feedback circuit 102 has a preset bus voltage value inside, and the output end of the feedback circuit 102 is connected with the negative phase input end of the comparator U1, and is used for generating a feedback signal according to the preset bus voltage value and the voltage at two ends of the bus capacitor and outputting the feedback signal to the negative phase input end of the comparator U1; the output terminal of the comparator U1, serving as the output terminal of the control circuit 10, is connected to the control switch S1, and is configured to generate a control signal according to the triangular wave signal and the feedback signal, and output the control signal to the control switch S1.
For example, as shown in fig. 4, LG represents a driving signal of the lower switch Q2, X2 represents a triangular wave signal (specifically, a sawtooth wave here), X3 represents a feedback signal, X4 represents a control signal for controlling the switch S1, and TON represents a high-level time of the control signal. The triangular wave generating circuit 101 inputs the driving signal LG of the lower switch tube Q2, and the triangular wave generating circuit 101 instantly rises to a high level (the slope is close to 90 degrees) at the falling edge of the driving signal of the lower switch tube Q2, and then falls according to a certain slope (the slope is smaller than 90 degrees) so as to generate and output a sawtooth wave signal; the comparator U1 compares the triangular wave signal X2 with the feedback signal X3 to output a control signal X4 for controlling the control switch S1. The feedback circuit 102 sets a preset value of bus voltage, the higher the voltage across the bus capacitor is, the smaller the feedback signal X3 is, so that the longer the high level time of the control signal X4 is, the longer the on-time of the control switch S1 is, the shorter the accumulation time for the charge pump circuit to shunt the resonant current is, the more the energy on the bus capacitor is released to the rear stage, and the voltage across the bus capacitor drops to the preset value of bus voltage. Vice versa, therefore, the purpose of adjusting the voltage across the bus capacitor is achieved, so that the voltage is stabilized at the preset value of the bus voltage set by the feedback circuit 102.
Further, referring to fig. 5, in a specific embodiment, the triangular wave generating circuit 101 includes: a controllable switch S2, a first voltage source VCC1, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C4, and a second capacitor C5; the first voltage source VCC1 is connected to the first end of the first resistor R1 and the second end of the controllable switch S2, the second end of the first resistor R1 is connected to the first end of the controllable switch S2 and the first end of the second resistor R2, the second end of the second resistor R2 is connected to the first end of the first capacitor C4, the second end of the first capacitor C4 is connected to the driving end of the lower switch tube of the main resonant circuit and used for obtaining the driving signal LG of the lower switch tube, the third end of the controllable switch S2 is connected to the first common end of the third resistor R3 and the second common end of the second capacitor C5 which are connected in parallel and used as the output end of the triangular wave generating circuit, and the second common end of the third resistor R3 and the second capacitor C5 which are connected in parallel is grounded.
The controllable switch S2 may be a PNP transistor; the base electrode of the PNP type triode is the first end of the switch tube, the emitter electrode of the PNP type triode is the second end of the switch tube, and the collector electrode of the PNP type triode is the third end of the switch tube.
Specifically, the base of the PNP type triode is connected to the first voltage source VCC1 through the first resistor R1, and is connected in series with the driving end of the switching tube Q2 of the resonance main circuit through the second resistor R2R2 and the first capacitor C4, the collector of the PNP type triode is connected to the first common end of the third resistor R3 and the second capacitor C5 and serves as the output end of the triangular wave generating circuit 101, and the emitter of the PNP type triode is directly connected to the first voltage source VCC 1.
The amplitude of the first voltage source VCC1 is selected in relation to the amplitude of the driving signal LG and the resistances of the first resistor R1 and the second resistor R2R2, and it is required to satisfy the following conditions: when the driving signal LG is in a high level, the current of the PNP type triode is not enough to enable the PNP triode to be conducted.
The driving signal LG is at a high level before the falling edge moment, no current flows through the base electrode of the PNP type triode in the period, the PNP type triode is cut off, and the output end of the triangular wave generating circuit 101 is at a zero level; in the falling edge process of the driving signal LG, the driving signal LG jumps from a high level to a low level instantly, the first voltage source VCC1 divides voltage through the first resistor R1 and the second resistor R2 to provide current for the PNP type triode to force the PNP type triode to be conducted, the output end of the triangular wave generating circuit 101 rises to a high level instantly (the slope is close to 90 degrees), the first capacitor C4 charges, the voltage of the point a shown in the figure is rapidly charged to the voltage value of the first voltage source, the PNP type triode stops conducting, the voltage of the output end of the triangular wave generating circuit 101 drops according to a certain slope (the slope is smaller than 90 degrees) under the discharging action of the third resistor R3 and the second capacitor C5, and accordingly a triangular wave signal is generated, specifically, the triangular wave signal is a sawtooth wave.
Further, referring to fig. 6, in a specific embodiment, the feedback circuit 102 includes: an operational amplifier U2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a third capacitor C6; the fourth resistor R4 and the fifth resistor R5 are connected in series and then connected to two ends of the bus capacitor, and the inverting input terminal of the operational amplifier U2 is connected to one end of the fourth resistor R4 connected to the fifth resistor R5, that is, the inverting input terminal inputs the bus voltage. The non-inverting terminal of the operational amplifier U2 inputs a reference signal, the output terminal of the operational amplifier U2 serves as the output terminal of the feedback circuit 102, the output terminal of the operational amplifier U2 is connected in series with the third capacitor C6 and the sixth resistor R6 and then connected to the negative input terminal of the operational amplifier U2, the other terminal of the fourth resistor R4 is connected to the voltage at the two terminals of the bus capacitor, and the other terminal of the fifth resistor R5 is grounded.
Specifically, the sixth resistor R6 and the third capacitor C6 are connected in series to form an operational amplifier loop, and are connected in parallel to the output terminal and the negative phase input terminal of the operational amplifier U2. The fourth resistor R4 and the fifth resistor R5 divide and sample the voltage across the bus capacitor, and input the divided voltage signal to the negative phase input terminal of the operational amplifier U2, the reference signal Vref is input to the positive phase input terminal of the operational amplifier U2, and the operational amplifier U2 compares the signal at the positive phase input terminal with the signal at the negative phase input terminal, performs proportional-integral operation through an operational amplifier loop, and outputs a feedback signal.
The reference signal Vref is used to set a preset bus voltage value, i.e., the preset bus voltage value VC1 ═ (Vref (R4+ R5))/R5.
Further, referring to fig. 7, in another specific embodiment, the feedback circuit 102 includes: a three-terminal regulator tube U3, a second voltage source VCC2, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10 and a fourth capacitor C7; the cathode of the three-terminal regulator tube U3 is used as the output end of the feedback circuit 102, the cathode of the three-terminal regulator tube U3 is connected with the second voltage source after being connected with the tenth resistor R10 in series, the anode of the three-terminal regulator tube U3 is connected with one end of the eighth resistor R8 and is grounded, the other end of the eighth resistor R8 is connected with one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected with the voltage at two ends of the bus capacitor, the reference end of the three-terminal regulator tube U3 is connected with the fourth capacitor C7 and the ninth resistor R9 in series and is connected with the cathode of the three-terminal regulator tube U3, the seventh resistor R7 and the eighth resistor R8 are connected with two ends of the bus capacitor after being connected in series, and the reference end of the three-terminal regulator tube U3 is connected between the seventh resistor R7 and the eighth resistor R8.
Specifically, in the embodiment, the feedback circuit 102 includes a three-terminal regulator U3, seventh to tenth resistors R7 to R10, and a fourth capacitor C7. The ninth resistor R9, the tenth resistor R10, the fourth capacitor C7 and the second voltage source VCC2 form a feedback loop. The seventh resistor R7 and the eighth resistor R8 divide the voltage at two ends of the bus capacitor, and connect a divided voltage signal with a reference end of the three-terminal voltage regulator tube U3, the anode of the three-terminal voltage regulator tube U3 is connected with the common ground, and the cathode of the three-terminal voltage regulator tube U3 is connected to the second voltage source VCC2 through the tenth resistor R10. A reference signal Vref2 is arranged in the three-terminal regulator tube U3 and is compared with an input signal of a reference end of the three-terminal regulator tube U3, and the three-terminal regulator tube U3 carries out operation through a feedback loop according to the signal of the reference end and outputs a feedback signal;
the reference signal Vref2 inside the three-terminal regulator tube U3 is used for setting a preset bus voltage value, that is, the preset bus voltage value VC1 is (Vref2 (R7+ R8))/R8.
In summary, the charge pump control circuit provided in the present application includes a control switch and a control circuit, the control switch is connected in parallel to two ends of the charge pump circuit, and the control circuit is used for controlling the on-off state of the control switch. Specifically, the control circuit is used for controlling the switch state of the control switch according to a feedback signal related to the voltage at two ends of the bus capacitor and a driving signal of a switch tube in the resonance main circuit, so that the control switch is conducted within the time of passing a forward resonance current in the resonance main circuit, the charge pump circuit is short-circuited, and the bus capacitor releases electric energy to a post-stage circuit, because the feedback signal is in negative correlation with the voltage at the two ends of the bus capacitor, and the conduction time of the control switch is in negative correlation with the magnitude of the feedback signal, therefore, the larger the voltage at the two ends of the bus capacitor is, the smaller the feedback signal is, the longer the time for controlling the switch to be conducted is, the more electric energy can be released to the backward stage circuit by the bus capacitor, and then the voltage at the two ends of the bus capacitor is reduced, the voltage at the two ends of the bus capacitor is stabilized at a certain voltage value, and the voltage pressure on devices of a later-stage circuit caused by overhigh voltage of the bus capacitor is avoided.
The present application further provides a driving power supply, as shown in fig. 2, including a rectifier bridge BD1, a bus capacitor C1, a resonant main circuit, a charge pump circuit, a resonant control circuit, and a charge pump control circuit as described in the above embodiments. The rectifier bridge BD1 is used for converting the input alternating voltage into a rectified voltage and outputting the rectified voltage; the resonance control circuit is used for collecting output parameters of the resonance main circuit, and controlling a switch tube Q1 and a switch tube Q2 in the resonance main circuit according to the output parameters, so that the resonance main circuit outputs stable output voltage or output current. Specifically, referring to fig. 8, the resonance control circuit includes a voltage-controlled oscillator and a drive control circuit; the input end of the voltage-controlled oscillator collects output parameters of the main resonant circuit, and the output end of the voltage-controlled oscillator outputs a frequency control signal V1 to the drive control circuit. The voltage-controlled oscillator adjusts the frequency of the output frequency control signal V1 according to the magnitude of a parameter characterizing the output voltage or output current of the resonant main circuit. The driving control circuit outputs a driving signal according to the frequency control signal V1 to control the switching tube Q1 and the switching tube Q2 in the resonant main circuit, so that the resonant main circuit outputs stable output voltage or output current.
The charge pump circuit comprises a diode D1 and a capacitor C2, when the resonant current is in a positive direction and the control switch is turned off, the resonant current charges a capacitor C2 in the charge pump circuit until the voltage value of the capacitor C2 is equal to the difference between the rectified value of the input voltage and the voltage of the bus capacitor C1, at the moment, the charging is stopped, and the resonant current forms a loop with the input power supply through a rectifier bridge BD 1. A diode D1 in the charge pump circuit provides a current return for the resonant current when the resonant current is in reverse.
When the control switch in the charge pump control circuit is an MOS (metal oxide semiconductor) transistor, the charge pump circuit and the MOS transistor share a parasitic diode of the MOS transistor. In other words, the charge pump circuit does not need to be additionally provided with a diode, and only the capacitor is reserved.
For the charge pump control circuit in the driving power supply, reference may be made to the related embodiments of the charge pump control circuit, which is not described herein again.
Because the situation is complicated and cannot be illustrated by a list, those skilled in the art can appreciate that there can be many examples in combination with the actual situation under the basic principle of the embodiments provided in the present application and that it is within the scope of the present application without sufficient inventive effort.
The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The charge pump control circuit and the driving power supply provided by the present application are described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Claims (9)
1. A charge pump control circuit, comprising:
a control switch and a control circuit; the control switch is connected in parallel with two ends of the charge pump circuit, and the control end of the control switch is connected with the output end of the control circuit;
the control circuit is used for generating a feedback signal according to the voltage at two ends of the bus capacitor, generating a triangular wave signal according to a driving signal of a switching tube in the resonant main circuit, comparing the feedback signal with the triangular wave signal, controlling the control switch to be switched on when the triangular wave signal is greater than the feedback signal so as to short circuit the charge pump circuit, and controlling the control switch to be switched off when the triangular wave signal is not greater than the feedback signal;
the switching tube comprises an upper switching tube and a lower switching tube which are in a bridge structure; the magnitude of the feedback signal is in negative correlation with the magnitude of the voltage at two ends of the bus capacitor, and the conduction time of the control switch is in negative correlation with the magnitude of the feedback signal.
2. The charge pump control circuit of claim 1, wherein the control circuit comprises:
the circuit comprises a comparator, a triangular wave generating circuit and a feedback circuit; wherein the driving signal is a driving signal of the lower switching tube;
the input end of the triangular wave generating circuit inputs the driving signal, and the output end of the triangular wave generating circuit is connected with the in-phase end of the comparator and used for generating a triangular wave signal according to the driving signal and outputting the triangular wave signal to the in-phase end of the comparator; the starting time of the triangular wave signal is the turn-off time of the lower switching tube; the signal period of the triangular wave signal is the signal period of the driving signal;
the input end of the feedback circuit inputs a reference signal and voltages at two ends of the bus capacitor, and the output end of the feedback circuit is connected with the negative phase input end of the comparator and is used for generating the feedback signal according to the reference signal and the voltages at two ends of the bus capacitor and outputting the feedback signal to the negative phase input end of the comparator;
the output end of the comparator is used as the output end of the control circuit, is connected with the control switch, and is used for generating a control signal according to the triangular wave signal and the feedback signal and outputting the control signal to the control switch.
3. The charge pump control circuit of claim 2, wherein the triangular wave generation circuit comprises:
the controllable switch, a first voltage source, a first resistor, a second resistor, a third resistor, a first capacitor and a second capacitor;
the first voltage source is connected with a first end of the first resistor and a second end of the controllable switch, a second end of the first resistor is connected with a first end of the controllable switch and a first end of the second resistor, a second end of the second resistor is connected with a first end of the first capacitor, a second end of the first capacitor is connected with a driving signal of the switch tube of the resonance main circuit, a third end of the controllable switch is connected with a first common end of the third resistor and the second capacitor after being connected in parallel and serves as an output end of the triangular wave generation circuit, and a second common end of the third resistor and the second capacitor after being connected in parallel is grounded.
4. The charge pump control circuit of claim 3, wherein the controllable switch is a PNP type triode; the base electrode of the PNP type triode is the first end of the controllable switch, the emitter electrode of the PNP type triode is the second end of the controllable switch, and the collector electrode of the PNP type triode is the third end of the controllable switch.
5. The charge pump control circuit of claim 2, wherein the feedback circuit comprises:
the operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor and a third capacitor; the fourth resistor is connected with the fifth resistor in series at two ends of the bus capacitor, the inverting input end of the operational amplifier is connected with one end of the fourth resistor connected with the fifth resistor, the same-phase end of the operational amplifier inputs a reference signal, the output end of the operational amplifier serves as the output end of the feedback circuit, the output end of the operational amplifier is connected with the third capacitor in series and connected with the negative-phase input end of the operational amplifier behind the sixth resistor, the other end of the fourth resistor is connected with the voltages at two ends of the bus capacitor, and the other end of the fifth resistor is grounded.
6. The charge pump control circuit of claim 2, wherein the feedback circuit comprises:
the three-terminal voltage regulator tube, the second voltage source, the seventh resistor, the eighth resistor, the ninth resistor, the tenth resistor and the fourth capacitor;
the cathode of the three-terminal voltage-stabilizing tube is used as the output end of the feedback circuit, the cathode of the three-terminal voltage-stabilizing tube is connected with the tenth resistor in series and then is connected with the second voltage source, the anode of the three-terminal voltage-stabilizing tube is connected with one end of the eighth resistor and is grounded, the other end of the eighth resistor is connected with one end of the seventh resistor, the other end of the seventh resistor is connected with the voltage at two ends of the bus capacitor, the reference end of the three-terminal voltage-stabilizing tube is connected with the fourth capacitor and the ninth resistor in series and then is connected with the cathode of the three-terminal voltage-stabilizing tube, the seventh resistor and the eighth resistor are connected with two ends of the bus capacitor in series and the reference end of the three-terminal voltage-stabilizing tube is connected between the seventh resistor and the eighth resistor.
7. The charge pump control circuit of claim 1, wherein the control switch is a MOS transistor.
8. A drive power supply, comprising:
rectifier bridge, bus capacitor, resonant main circuit, charge pump circuit, resonant control circuit and charge pump control circuit according to any of claims 1 to 7.
9. The driving power supply according to claim 8, wherein when the control switch in the charge pump control circuit is a MOS transistor, the charge pump circuit and the MOS transistor share a parasitic diode of the MOS transistor.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010538156.0A CN111629496B (en) | 2020-06-12 | 2020-06-12 | Charge pump control circuit and driving power supply |
| PCT/CN2021/098593 WO2021249332A1 (en) | 2020-06-12 | 2021-06-07 | Charge pump control circuit and driving power source |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010538156.0A CN111629496B (en) | 2020-06-12 | 2020-06-12 | Charge pump control circuit and driving power supply |
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| CN111629496B true CN111629496B (en) | 2022-01-25 |
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| JP3475887B2 (en) * | 2000-01-11 | 2003-12-10 | 株式会社村田製作所 | Switching power supply |
| CN202385330U (en) * | 2011-09-06 | 2012-08-15 | 上海新进半导体制造有限公司 | LED driving circuit |
| US9185767B2 (en) * | 2013-04-19 | 2015-11-10 | Cirrus Logic, Inc. | Self-oscillating resonant converter-based light emitting diode (LED) driver |
| CN108631562A (en) * | 2017-03-16 | 2018-10-09 | 赤多尼科两合股份有限公司 | A kind of PFC charge pump circuits |
| CN107257194B (en) * | 2017-08-16 | 2024-04-02 | 英飞特电子（杭州）股份有限公司 | Resonant converter |
| CN109639151A (en) * | 2019-01-21 | 2019-04-16 | 杭州士兰微电子股份有限公司 | Constant-current control circuit and constant current control method for LLC resonant converter |
| CN110808681B (en) * | 2019-11-13 | 2021-06-29 | 杭州优特电源有限公司 | Passive PFC resonant converter and control method thereof |
| CN111629496B (en) * | 2020-06-12 | 2022-01-25 | 英飞特电子（杭州）股份有限公司 | Charge pump control circuit and driving power supply |
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| WO2021249332A1 (en) | 2021-12-16 |
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