CN214626787U - Switching power supply circuit and control chip applied to switching power supply - Google Patents
Switching power supply circuit and control chip applied to switching power supply Download PDFInfo
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- CN214626787U CN214626787U CN202120366156.7U CN202120366156U CN214626787U CN 214626787 U CN214626787 U CN 214626787U CN 202120366156 U CN202120366156 U CN 202120366156U CN 214626787 U CN214626787 U CN 214626787U
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Abstract
The application relates to a switching power supply circuit and a control chip applied to the switching power supply, comprising a mode identification module and a feedback voltage detection module, wherein the mode identification module comprises a first input end VS and a second input end VCC. The mode identification module identifies whether the switch power supply circuit is a flyback switch power supply circuit or a buck switch power supply circuit according to the access voltages of the first input end VS and the second input end VCC, and outputs the corresponding access voltage as a feedback signal to the feedback voltage detection module; the feedback voltage detection module is used for detecting the voltage signal output by the mode identification module and outputting a detection result to the PWM module so that the PWM module outputs a power supply switch signal subjected to pulse width modulation according to the detection result. The problems of complex design process, low efficiency and high cost caused by poor universality of the control chip of the existing switching power supply circuit can be solved.
Description
Technical Field
The application relates to a switching power supply circuit and a control chip applied to the switching power supply, and belongs to the technical field of switching power supplies.
Background
With the increasingly complex functions of electronic equipment, the requirements of the electronic equipment on the switching power supply are increasingly high, and the switching power supply technology is unprecedentedly developed. In order to manage wider loads, lower output voltage and synchronization of multiple power supplies, more and more electronic products or household appliances adopt a Buck power supply and a Flyback power supply at present.
Although the Buck power supply and the Flyback power supply have larger structural difference, the control principle is basically consistent, so if one power supply chip can be simultaneously applied to switching power supplies with two different structures, the generalization of the power supply control chip can be realized, the waste of resources is avoided, the design efficiency of the power supply is improved, and the design cost is reduced.
SUMMERY OF THE UTILITY MODEL
The application provides a switching power supply circuit and be applied to switching power supply's control chip, can solve current switching power supply circuit control chip commonality poor, lead to the problem that the design process is complicated, inefficiency, with high costs.
The application provides the following technical scheme:
in a first aspect, a control chip applied to a switching power supply is provided, which includes a feedback voltage detection module and a PWM module, where the feedback voltage detection module is configured to detect a voltage signal at an output end of the power supply, an output end of the feedback voltage detection module is connected to the PWM module, and the PWM module is configured to output a power supply switching signal subjected to pulse width modulation; the control chip further comprises a mode identification module, the mode identification module comprises a first input end VS and a second input end VCC, and a feedback signal output end of the mode identification module is connected with an input end of the feedback voltage detection module;
when the control chip is connected to the flyback switching power supply circuit, the first input end VS is connected with a power supply output end, the mode identification module connects the first input end VS with the second input end VCC according to input signals of the first input end VS and the second input end VCC to supply power for the control chip, and meanwhile, a voltage signal connected to the first input end VS is used as a feedback signal to be output to the feedback voltage detection module;
when the control chip is connected into the buck switching power supply circuit, the first input end VS is suspended, the second input end VCC is connected with the power supply output end, the second input end VCC serves as a power supply end of the control chip, and the mode recognition module outputs a voltage signal connected into the second input end VCC to the feedback voltage detection module as a feedback signal according to input signals of the first input end VS and the second input end VCC.
Further, according to the control chip of the first aspect of the present application, the pattern recognition module includes a first control circuit and a second control circuit, and a first switch, a second switch, and a third switch;
the first switch is connected between the first input end and the second input end;
the second switch is connected between the first input end and the feedback signal output end;
the third switch is connected between the second input end and the feedback signal output end;
the input end of the first control circuit is respectively connected with the first input end and the second input end, and the output end of the first control circuit is connected with the control end of the first switch;
the input end of the second control circuit is respectively connected with the first input end and the reference voltage signal, and the output end of the second control circuit outputs two paths of control signals, wherein one path of control signal is connected with the control end of the second switch, and the other path of control signal is connected with the control end of the third switch;
when the control chip is connected to the flyback switch power supply circuit, the first control circuit is used for controlling the first switch to be switched on, and the second control circuit is used for controlling the second switch to be switched on and controlling the third switch to be switched off;
when the control chip is connected to the buck switch power supply circuit, the first control circuit is used for controlling the first switch to be turned off, and the second control circuit is used for controlling the second switch to be turned off and controlling the third switch to be turned on.
Further, according to the control chip of the first aspect of the present application, the first control circuit includes a first comparator, a non-inverting input terminal of the first comparator is connected to the first input terminal, an inverting input terminal of the first comparator is connected to the second input terminal, and an output terminal of the first comparator is connected to the control terminal of the first switch;
the second control circuit comprises a second comparator and a third phase inverter, the non-inverting input end of the second comparator is connected with the first input end, the inverting input end of the second comparator is connected with the reference voltage, the output end of the second comparator is connected with the control end of the second switch, and the output end of the second comparator is connected with the control end of the third switch through the third phase inverter.
Further, according to the control chip of the first aspect of the present application, the first control circuit further includes a first memory circuit, and the second control circuit further includes a second memory circuit, a first and gate, and a second and gate;
the first memory circuit is connected between the first comparator and the first switch, an output signal of the first comparator and an initial signal of the switch power supply during starting are respectively connected to two input ends of the first memory circuit, and an output end of the first memory circuit is connected with a control end of the first switch;
the output signal of the second comparator and the initial signal of the switching power supply during starting are respectively connected to two input ends of a second memory circuit, the output end of the second memory circuit outputs two paths of control signals, wherein one path of control signal is connected to one input end of the first AND gate, and the other path of control signal is connected to one input end of the second AND gate through a third inverter;
the other input ends of the first AND gate and the second AND gate are both connected with an initial signal when the switching power supply is started, the output end of the first AND gate is connected with the control end of the second switch, and the output end of the second AND gate is connected with the control end of the third switch.
Further, according to the control chip of the first aspect of the present application, the first memory circuit includes a first RS flip-flop and a first inverter, and the second memory circuit includes a second RS flip-flop and a second inverter;
a set end of the first RS trigger is connected with an output signal of the first comparator, an initial signal when the switching power supply is started is connected with a reset end of the first RS trigger through the first phase inverter, and an output end of the first RS trigger is connected with a control end of the first switch;
the set end of the second RS trigger is connected with the output signal of the second comparator, the initial signal when the switching power supply is started is connected with the reset end of the second RS trigger through the second phase inverter, the output end of the second RS trigger is connected with one input end of the first AND gate, and meanwhile, the output end of the second RS trigger is connected with one input end of the second AND gate through the third phase inverter.
Further, according to the control chip of the first aspect of the present application, when the control chip is connected to the flyback switching power supply circuit, the second input terminal VCC is connected to the ground terminal of the control chip through the first capacitor; when the control chip is connected to the buck switching power supply circuit, the second input terminal VCC is connected to the ground terminal of the control chip through the second capacitor.
Further, according to this application first aspect the control chip, control chip includes high-pressure starting circuit, power input end is connected to high-pressure starting circuit's input, second input VCC is connected to high-pressure starting circuit's output, high-pressure starting circuit is used for when the system is electrified, charges for the first capacitance or the second capacitance of second input VCC, so that control chip normally starts.
Further, according to the control chip of the first aspect of the present application, the control chip further includes an oscillation circuit, an input end of the oscillation circuit is connected to an output end of the feedback voltage detection module, an output end of the oscillation circuit is connected to the PWM module, the oscillation circuit is configured to generate a working frequency of the switching power supply circuit, and the PWM module adjusts a frequency of the power switch signal according to the working frequency.
Further, according to the control chip of this application first aspect, control chip includes protection module, protection module connects the PWM module, protection module is used for when detecting system anomaly, sends the signal for the PWM module, through the PWM module will the switch tube of power supply cuts off.
In a second aspect, a switching power supply circuit is provided, which includes a Buck power supply or a Flyback power supply, and the switching power supply circuit further includes the control chip described in the first aspect, and the control chip is connected with a Buck power supply peripheral circuit to form a Buck switching power supply circuit; the control chip is connected with the Flyback power supply peripheral circuit to form a Flyback switching power supply circuit.
The beneficial effect of this application lies in: the application discloses a control chip for switching power supply circuit is provided with the mode identification module, can distinguish that what insert is step-down switching power supply circuit, still flyback switching power supply circuit to according to the switching power supply circuit of difference, with the first input that corresponds or the access voltage of second input is as feedback signal output, thereby makes this control chip both can be applied to flyback switching power supply circuit, also can be applied to step-down switching power supply circuit, has improved control chip's commonality and utilization ratio, has reduced manufacturing cost.
The foregoing description is only an overview of the technical solutions of the present application, and in order to make the technical solutions of the present application more clear and clear, and to implement the technical solutions according to the content of the description, the following detailed description is made with reference to the preferred embodiments of the present application and the accompanying drawings.
Drawings
Fig. 1 is a block diagram of a switching power supply according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a control chip according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of a circuit configuration of a pattern recognition module according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a circuit configuration of a pattern recognition module according to another embodiment of the present application;
fig. 5 is a circuit diagram of a control chip applied to a flyback switching power supply according to an embodiment of the present application;
FIG. 6 is a circuit diagram of a buck switching power supply with a control chip according to an embodiment of the present disclosure;
FIG. 7 is a schematic package diagram of an integrated design of a power switch tube and a control chip according to an embodiment of the present application;
fig. 8 is a package diagram of an integrated design of a power switching tube and a control chip according to another embodiment of the present application.
Detailed Description
The following detailed description of embodiments of the present application will be described in conjunction with the accompanying drawings and examples. The following examples are intended to illustrate the present application but are not intended to limit the scope of the present application.
A switching power supply, namely a switching stabilized voltage supply, is a novel stabilized voltage supply circuit relative to a linear stabilized voltage supply, and stabilizes output voltage by monitoring the output voltage in real time and dynamically controlling the on-off time ratio of a switching tube.
The switching power supply can adopt a Buck power supply topology or a Flyback power supply topology, wherein the Buck power supply topology forms a Buck switching power supply, and the Flyback power supply topology forms a Flyback switching power supply.
Fig. 1 is a block diagram of a switching power supply according to an embodiment of the present invention, and as shown in fig. 1, the switching power supply includes a Buck power supply or a Flyback power supply, and a corresponding control chip, where the control chip is connected to a power output terminal of the switching power supply to monitor a change of an output voltage of the switching power supply in real time. The driving signal output end of the control chip is connected with the control end of the power switch tube to control the on and off of the power switch tube, so that the pulse width or frequency of the power switch signal is dynamically adjusted in time, and stable output voltage is finally obtained.
Fig. 2 is a schematic structural diagram of a control chip applied to a switching power supply according to an embodiment of the present application, where as shown in fig. 2, the control chip includes:
and the input end of the feedback voltage detection module FB is connected with the power output voltage signal and used for processing the connected power output voltage signal and outputting the processed signal to the PWM module.
And the PWM (pulse width modulation) module is used for receiving the power output voltage signal output by the feedback voltage detection module FB and giving a corresponding PWM switching signal according to the change of the power output voltage.
And the driving module DRV is used for receiving the PWM switching signal output by the PWM module, converting the PWM switching signal into a driving signal and outputting the driving signal to the control end of the power switching tube so as to timely and dynamically adjust the ratio of the on-time to the off-time of the power switching tube and further obtain stable output voltage. The power switch tube can be integrated in the control chip and can also be used as a peripheral circuit device of the control chip.
Further, the control chip of the embodiment of the present application further includes:
the input end of the current detection module CS is connected into the switching power supply loop, and the output end of the current detection module CS is connected with the PWM module. The current detection module CS is used for detecting the current of the switching power supply loop and outputting the detection result to the PWM module so that the PWM module adjusts the pulse width of the power supply switching signal according to the current signal and the voltage signal output by the feedback voltage detection module FB.
The input end of the oscillation circuit is connected with the feedback voltage detection module FB, the output end of the oscillation circuit OSC is connected with the PWM module, and the oscillation circuit OSC is used for receiving the power supply output voltage signal detected by the feedback voltage detection module FB, generating the working frequency of the switching power supply according to the power supply output voltage signal and then outputting the working frequency to the PWM module so that the PWM module adjusts the frequency of the power supply switching signal according to the working frequency
And the high-voltage starting circuit HV is used for ensuring the normal starting of the control chip when a system where the switching power supply is positioned is electrified.
Optionally, the control chip of the embodiment of the present application is further provided with a protection module PRO, where the protection module PRO is configured to turn off the power switching tube Q1 through the PWM module when the system abnormality is detected. The power switch Q1 is connected to the loop of the BUCK switch power supply or the Flyback switch power supply, and the power switch Q1 may be integrated inside the chip or external.
Further, the control chip of the embodiment of the application further includes a pattern recognition module DET, and the pattern recognition module DET is used for recognizing whether a system where the control chip is located is a flyback switching power supply or a buck switching power supply.
Specifically, the pattern recognition module DET is provided with a first input terminal VS and a second input terminal VCC, wherein when the control chip is connected to the flyback switching power supply circuit, the voltage of the power supply output terminal is connected through the first input terminal VS; when the control chip is connected to the voltage reduction type switch power supply circuit, the voltage of the power supply output end is accessed through the second input end VCC. The mode identification module judges whether a system where the control chip is located is a flyback switching power supply or a buck switching power supply according to input signals of a first input end VS and a second input end VCC, and a feedback signal output end of the mode identification module is connected with a feedback voltage detection module FB.
Simultaneously second input VCC connects high-voltage starting circuit's output, for control chip power supply when switching power supply is last, guarantees that control chip can normally start, just second input VCC supplies power for control chip as control chip's working power supply, guarantees that control chip can normally work.
Fig. 3 is a schematic diagram of a circuit structure of a pattern recognition module according to an embodiment of the present application, and as shown in fig. 3, the pattern recognition module includes a first control circuit 1, a second control circuit 2, a first switch K1, a second switch K2, and a third switch K3.
Wherein, the first control circuit 1 is used for controlling the first switch K1 to be switched on when the control chip is switched in the flyback switching power supply circuit, and controlling the first switch K1 to be switched off when the control chip is switched in the buck switching power supply circuit,
the second control circuit 2 is used for controlling the second switch K2 to be switched on and controlling the third switch K3 to be switched off when the control chip is switched into the flyback switching power supply circuit; when the control chip is connected to the buck switching power supply circuit, the second switch K2 is controlled to be turned off, and the third switch K3 is controlled to be turned on.
As shown in fig. 3, the first control circuit 1 of the present embodiment includes a first comparator COM1, and the second control circuit 2 includes a second comparator COM2 and a third inverter INV 3.
The mode identification module is provided with a feedback signal output end, a first input end VS and a second input end VCC, wherein the first input end VS is connected to the ground through a resistor RVS in a default mode, the VS is in a low level in a default mode when the VS end is suspended, and the second input end VCC serves as a power supply end of the control chip.
The non-inverting input end of the first comparator COM1 is connected to the first input end VS, the inverting input end of the first comparator COM1 is connected to the second input end VCC, the output end of the first comparator COM1 is connected to the control end of the first switch K1, one end of the first switch K1 is connected to the first input end VS, and the other end of the first switch K1 is connected to the second input end VCC.
The non-inverting input end of the second comparator COM2 is connected to the first input end VS, the inverting input end of the second comparator COM2 is connected to the reference voltage VREF, the output end of the second comparator COM2 is connected to the control end of the second switch K2, one end of the second switch K2 is connected to the first input end VS, and the other end of the second switch K2 is connected to the feedback signal output end of the pattern recognition module DET.
The output end of the second comparator COM2 is further connected to the control end of the third switch K3 through a third inverter INV 3. One end of the third switch K3 is connected to the feedback signal output end of the mode identification module DET, and the other end of the third switch K3 is connected to the second input end VCC.
Fig. 4 is a schematic circuit diagram of a pattern recognition module according to another embodiment of the present application, AND as shown in fig. 4, based on the embodiment shown in fig. 3, the first control circuit 1 of the pattern recognition module according to this embodiment includes a first comparator COM1 AND a first memory circuit, AND the second control circuit 2 includes a second memory circuit, a first AND gate AND1 AND a second AND gate AND2, where the first memory circuit includes a first RS flip-flop RS1 AND a first inverter INV1, AND the second memory circuit includes a second RS flip-flop RS2 AND a second inverter INV 2.
The first input end VS is connected to the ground through a resistor RVS in a default mode, the VS is in a low level in a default mode when the VS end is suspended, and the second input end VCC serves as a power supply end of the control chip and provides power supply voltage for the control chip.
The non-inverting input end of the first comparator COM1 is connected with the first input end VS, the inverting input end of the first comparator COM1 is connected with the second input end VCC, the output end of the first comparator COM1 is connected with the set end of the first RS trigger RS1, an initial signal PG when the switching power supply is started is connected with the reset end of the first RS trigger RS1 through the first inverter INV1, the output end of the first RS trigger RS1 is connected with the control end of the first switch K1, one end of the first switch K1 is connected with the first input end VS, and the other end of the first switch K1 is connected with the second input end VCC.
The non-inverting input end of the second comparator COM2 is connected to the first input end VS, the inverting input end of the second comparator COM2 is connected to the reference voltage VREF, the output end of the second comparator COM2 is connected to the set end of the second RS flip-flop RS2, the initial signal PG when the switching power supply is started is connected to the reset end of the second RS flip-flop RS2 through the second inverter INV2, the output end of the second RS flip-flop RS2 is connected to one input end of the first AND gate 1, the initial signal PG when the switching power supply is started is connected to the other input end of the first AND gate AND1, the output end of the first AND gate 1 is connected to the control end of the second switch K2, one end of the second switch K2 is connected to the first input end VS, AND the other end of the second switch K2 is connected to the feedback signal output end of the mode identification module DET.
The output end of the second RS flip-flop RS2 is further connected to one input end of the second AND-gate AND2 through the third inverter INV3, the initial signal PG when the switching power supply is started is connected to the other input end of the second AND-gate AND2, the output end of the second AND-gate AND2 is connected to the control end of the third switch K3, one end of the third switch K3 is connected to the feedback signal output end, AND the other end of the third switch K3 is connected to the second input end VCC.
The present embodiment makes the control signals of the switches more stable by adding the first and second memory circuits and the initial signal PG.
In other embodiments, the first memory circuit and the second memory circuit may also select other circuits with memory function, such as: d flip-flops, JK flip-flops, latches, or integrated circuits of flip-flops and latches, etc., which are not limited herein.
Fig. 5 shows a circuit diagram of the control chip applied to the Flyback switching power supply, as shown in fig. 5, the control chip is connected to a Flyback power supply peripheral circuit to form a Flyback switching power supply circuit, when the control chip is applied to the Flyback switching power supply, the first input end VS of the pattern recognition module DET is directly connected to the power output end VOUT1, and the second input end VCC of the pattern recognition module is connected to the ground end GND of the control chip through the capacitor C4.
The present embodiment takes the application of the schematic diagram shown in fig. 4 in fig. 5 as an example to explain the working process of the present application: when the switching power supply is started, the high-voltage starting module HV starts to work, firstly, the VCC capacitor C4 is charged through the high-voltage starting module HV, the voltage of the second input terminal VCC slowly rises, meanwhile, the initial signal PG is at a low level, the first RS flip-flop RS1 resets to output the low level, the first switch K1 is turned off, the first AND gate AND1 AND the second AND gate AND2 both output low level signals, therefore, the second switch K2 AND the third switch K3 are both turned off, until the control chip is normally started, the high-voltage starting module HV is turned off, the initial signal PG is converted into the high level, AND meanwhile, the VCC voltage of the second input terminal VCC of the mode identification module DET is reduced accordingly.
Along with the reduction of the voltage of the second input end VCC, when the voltage of the first input end VS is higher than the voltage of the VCC end, the first comparator COM1 outputs a high level, the first RS trigger RS1 sets to output the high level, the first switch K1 is closed, the first input end VS is connected with the second input end VCC, and the second input end VCC supplies power through the power output end VOUT1 connected with the first input end VS, so that the control chip works normally.
After the control chip works normally, at this time, the voltage of the first input end VS is greater than the reference voltage VREF, the second comparator COM2 outputs a high level, the second RS flip-flop RS2 triggers to output a high level, AND at this time, PG is high, so the first AND gate AND1 outputs a high level, the second switch K2 is closed, the second AND gate AND2 outputs a low level, the third switch K3 is opened, AND the voltage signal of the first input end VS is output as a feedback signal through the feedback signal output end AND finally connected to the feedback voltage detection module FB.
In the flyback switching power supply shown in fig. 5, when the control chip is normally started and the voltage of the second input VCC is stable, the mode identification module DET determines that the second input VCC is connected to the first input VS, and the second input VCC supplies power to the control chip through the first input VS, so that the control chip is ensured to normally work, and meanwhile, the input voltage of the first input VS is used as a feedback signal to be accessed to the feedback voltage detection module FB.
The feedback voltage detection module FB accesses the processed feedback signal to the PWM module and the oscillation circuit OSC to output a pulse width modulated switching signal to the driving module DRV, and the driving module DRV converts the switching signal into a driving signal and outputs the driving signal to the Q1 to control the on-off time of the Q1, thereby adjusting the pulse width or frequency of the power switching signal and finally obtaining a stable output voltage.
Fig. 6 shows a circuit diagram of the control chip applied to the BUCK switching power supply according to the embodiment of the present invention, as shown in fig. 6, the control chip is connected to a peripheral circuit of the BUCK power supply to form a BUCK switching power supply circuit, when the control chip is applied to the BUCK switching power supply, the first input terminal VS of the pattern recognition module DET is floating, the second input terminal VCC of the pattern recognition module DET is connected to the power output terminal VOUT2 through the diode D2, and the second input terminal VCC of the pattern recognition module DET is connected to the ground terminal GND of the control chip through the capacitor C2.
The present embodiment takes the application of the schematic diagram shown in fig. 4 in fig. 6 as an example to explain the working process of the present application: after the switching power supply is started, the control chip starts to work, firstly, the capacitor C2 of the second input end VCC is charged through the high-voltage starting module, the voltage of the second input end VCC is slowly increased, meanwhile, because the initial signal PG is a low-level signal, the first RS trigger is reset to output a low-level signal, the first switch K1 is disconnected, the first AND gate AND1 AND the second AND gate AND2 both output low-level signals, AND therefore the second switch K2 AND the third switch K3 are both disconnected. Until the control chip is normally started, the high-voltage starting module HV is turned off, the initial signal PG is converted into a high level, and the second input terminal VCC of the mode identification module DET is connected to the voltage of the power output terminal VOUT2 through the diode D2 to supply power to the control chip.
After the control chip is normally started, at this time, since the initial signal PG is converted into a high level, VS is defaulted to a low level, AND the power output terminal VOUT2 is connected to the second input terminal VCC of the mode identification module DET through the diode D2, therefore, the second input terminal VCC is a high level, the outputs of the first comparator COM1 AND the second comparator COM2 are both a low level, the first RS flip-flop AND the second RS flip-flop are not set AND also both output a low level signal, the first AND gate AND1 outputs a low level signal, the second AND gate AND2 outputs a high level signal, so that both K1 AND K2 are open, AND K3 is closed, AND at this time, the voltage signal of the second input terminal VCC is output as a feedback signal through the feedback signal output terminal AND is finally connected to the feedback voltage detection module FB.
In the buck switching power supply shown in fig. 6, when the control chip is normally started and the voltage of the second input VCC is stable, the mode identification module DET determines that the voltage signal of the VCC terminal is used as a feedback signal to be connected to the feedback voltage detection module FB, the feedback voltage detection module FB connects the processed feedback signal to the PWM module and the oscillation circuit OSC to output a pulse width modulated switching signal to the driving module DRV, and the driving module DRV converts the switching signal into a driving signal to be output to the Q1 to control the on-off time of the Q1, thereby adjusting the pulse width or frequency of the power switching signal and finally obtaining a stable output voltage.
In the embodiment of the switching power supply circuit shown in fig. 5 and 6, the power switching tube Q1 is integrated inside the control chip, and in the flyback switching power supply shown in fig. 5, the control chip is connected to the primary coil through the collector C port of the power switching tube Q1, so as to be connected to the power supply loop. In the buck switching power supply shown in fig. 6, the control chip is connected to the power supply loop through the collector C and emitter port of the power switching transistor Q1. In the control chip, a base B of the power switch Q1 is used as a control terminal and connected to a driving signal output terminal of the driving module DRV, and an emitter of the power switch Q1 is connected to an input terminal of the current detection module CS.
Fig. 7 is a schematic package diagram of an integrated design of a power switch tube and a control chip provided in an embodiment of the present application, and as shown in fig. 7, the control chip of this embodiment adopts an SOP (chip on package) package with 8 pins, the package structure includes a control chip internal circuit 9, a power switch tube Q1 and a package body 10, where the package body 10 encapsulates the control chip internal circuit 9 and the power switch tube Q1. Please refer to the above embodiments of the control chip for the internal circuit 9 of the control chip, which is not described herein again.
In this embodiment, the 8 pins are respectively: a ground terminal pin VSS, two second detection voltage input pins VCC, a first detection voltage input pin VS and four high voltage start signal input pins HV.
In this embodiment, the pins with numbers 1 to 4 are disposed on one side of the control chip package structure, and the pins with numbers 5 to 8 are disposed on the other side of the control chip package structure, wherein:
the pins with the numbers of 1 and 3 are connected together, and are also the second detection voltage input pin VCC of the control chip, and the pin is electrically connected with the second input VCC of the control chip mode identification module and has the same function as the second input VCC.
The pin numbered 4 is a first detection voltage input pin VS of the control chip, and the pin is electrically connected with the first input end VS of the control chip mode identification module and has the same function as the first input end VS.
The pins with the numbers of 5 to 8 are connected together and are used as a high-voltage starting signal input pin HV, and the pin is electrically connected with the input end of the high-voltage starting module and has the same function as the high-voltage starting module.
The pin numbered 2 is a ground pin and is electrically connected to the ground PVSS/VSS of the control chip.
In the control chip packaging structure, the emission set E of the power switch tube Q1 is connected with the current detection module CS, and the base B of the power switch tube Q1 is connected with the driving module DRV.
Fig. 8 is a schematic package diagram of an integrated design of a switching tube and a control chip of a switching power supply according to another embodiment of the present application, where the control chip in this embodiment adopts a DIP (dual in-line package) package with 8 pins, and the package structure includes a control chip internal circuit 9, a power switching tube Q1, and a package body 10, where the package body 10 encapsulates the control chip internal circuit 9 and the power switching tube Q1. Please refer to the above embodiments of the control chip for the internal circuit 9 of the control chip, which is not described herein again.
The 8 pins are respectively as follows: the circuit comprises a grounding terminal pin VSS, a first detection voltage input pin VS, a second detection voltage input pin VCC, four high-voltage starting signal input pins HV and a floating pin NC.
In this embodiment, the pins with numbers 1 to 4 are disposed on one side of the control chip package structure, and the pins with numbers 5 to 8 are disposed on the other side of the control chip package structure, wherein:
the pin numbered 3 is a second detection voltage input pin VCC for the control chip mode identification module, and the pin is electrically connected with a second input VCC of the control chip mode identification module and has the same action as the second input VCC.
The pin numbered 4 is a first detection voltage input pin VS of the control chip, and the pin is electrically connected with the first input end VS of the control chip mode identification module and has the same function as the first input end VS.
The pins with the numbers of 5 to 8 are connected together and are used as a high-voltage starting signal input pin HV, and the pin is electrically connected with the input end of the high-voltage starting module and has the same function as the high-voltage starting module.
The pin numbered 1 is a ground pin and is electrically connected with the ground PVSS/VSS of the control chip.
The pin with the number 2 is suspended.
In the control chip packaging structure, the emission set E of the power switch tube Q1 is connected with the current detection module CS, and the base B of the power switch tube Q1 is connected with the driving module DRV.
It should be noted that, in other embodiments, the power switching tube Q1 may be externally disposed on the control chip, and the application is not limited herein.
The control chip of the embodiment of the application can be simultaneously suitable for the buck switching power supply and the flyback switching power supply, and the universality of the control chip is realized. The Buck power circuit or Flyback power circuit shown in fig. 4 and 5 are well known in the art, and will not be described herein.
To sum up, the control chip who is applied to switching power supply of this application is provided with the mode identification module, can distinguish that what insert is step-down switching power supply circuit, still flyback switching power supply circuit to according to the switching power supply circuit of difference, with the first input end that corresponds or the access voltage of second input is as feedback signal output, thereby makes this control chip both can be applied to flyback switching power supply circuit, also can be applied to step-down switching power supply circuit, has improved control chip's commonality and utilization ratio, has reduced manufacturing cost.
The embodiment of the application also provides a switching power supply circuit, which comprises a Buck power supply or a Flyback power supply, and the switching power supply circuit also comprises the control chip in the embodiment, wherein the control chip is connected with a Buck power supply peripheral circuit to form a Buck switching power supply circuit; and the control chip is connected with the Flyback circuit to form a Flyback switching power supply circuit.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (13)
1. A control chip applied to a switching power supply comprises a feedback voltage detection module and a PWM module, wherein the feedback voltage detection module is used for detecting a voltage signal at the output end of the power supply, the output end of the feedback voltage detection module is connected with the PWM module, and the PWM module is used for outputting a power supply switching signal subjected to pulse width modulation; the control chip is characterized by further comprising a mode identification module, wherein the mode identification module comprises a first input end VS and a second input end VCC, and a feedback signal output end of the mode identification module is connected with an input end of the feedback voltage detection module;
when the control chip is connected to the flyback switching power supply circuit, the first input end VS is connected with the power supply output end, the mode identification module is used for connecting the first input end VS with the second input end VCC through identifying input signals of the first input end VS and the second input end VCC so as to supply power for the control chip, and meanwhile, a voltage signal connected to the first input end VS is used as a feedback signal to be output to the feedback voltage detection module;
when the control chip is connected into the buck switching power supply circuit, the first input end VS is suspended, the second input end VCC is connected with the power output end, the second input end VCC serves as the power supply end of the control chip, and the mode recognition module outputs the voltage signal connected to the second input end VCC to the feedback voltage detection module as a feedback signal through recognition of input signals of the first input end VS and the second input end VCC.
2. The control chip of claim 1, wherein the pattern recognition module comprises a first control circuit and a second control circuit, and a first switch, a second switch, and a third switch;
the first switch is connected between the first input end and the second input end;
the second switch is connected between the first input end and the feedback signal output end;
the third switch is connected between the second input end and the feedback signal output end;
the input end of the first control circuit is respectively connected with the first input end and the second input end, and the output end of the first control circuit is connected with the control end of the first switch;
the input end of the second control circuit is respectively connected with the first input end and the reference voltage signal, and the output end of the second control circuit outputs two paths of control signals, wherein one path of control signal is connected with the control end of the second switch, and the other path of control signal is connected with the control end of the third switch;
when the control chip is connected to the flyback switch power supply circuit, the first control circuit is used for controlling the first switch to be switched on, and the second control circuit is used for controlling the second switch to be switched on and controlling the third switch to be switched off;
when the control chip is connected to the buck switch power supply circuit, the first control circuit is used for controlling the first switch to be turned off, and the second control circuit is used for controlling the second switch to be turned off and controlling the third switch to be turned on.
3. The control chip of claim 2, wherein the first control circuit comprises a first comparator, a non-inverting input terminal of the first comparator is connected to the first input terminal, an inverting input terminal of the first comparator is connected to the second input terminal, and an output terminal of the first comparator is connected to the control terminal of the first switch;
the second control circuit comprises a second comparator and a third phase inverter, the non-inverting input end of the second comparator is connected with the first input end, the inverting input end of the second comparator is connected with the reference voltage, the output end of the second comparator is connected with the control end of the second switch, and the output end of the second comparator is connected with the control end of the third switch through the third phase inverter.
4. The control chip of claim 3, wherein the first control circuit further comprises a first memory circuit, and the second control circuit further comprises a second memory circuit, a first AND gate, and a second AND gate;
the first memory circuit is connected between the first comparator and the first switch, an output signal of the first comparator and an initial signal of the switch power supply during starting are respectively connected to two input ends of the first memory circuit, and an output end of the first memory circuit is connected with a control end of the first switch;
the output signal of the second comparator and the initial signal of the switching power supply during starting are respectively connected to two input ends of a second memory circuit, the output end of the second memory circuit outputs two paths of control signals, wherein one path of control signal is connected to one input end of the first AND gate, and the other path of control signal is connected to one input end of the second AND gate through a third inverter;
the other input ends of the first AND gate and the second AND gate are both connected with an initial signal when the switching power supply is started, the output end of the first AND gate is connected with the control end of the second switch, and the output end of the second AND gate is connected with the control end of the third switch.
5. The control chip of claim 4, wherein the first memorizing circuit comprises a first RS flip-flop and a first inverter, and the second memorizing circuit comprises a second RS flip-flop and a second inverter;
a set end of the first RS trigger is connected with an output signal of the first comparator, an initial signal when the switching power supply is started is connected with a reset end of the first RS trigger through the first phase inverter, and an output end of the first RS trigger is connected with a control end of the first switch;
the set end of the second RS trigger is connected with the output signal of the second comparator, the initial signal when the switching power supply is started is connected with the reset end of the second RS trigger through the second phase inverter, the output end of the second RS trigger is connected with one input end of the first AND gate, and meanwhile, the output end of the second RS trigger is connected with one input end of the second AND gate through the third phase inverter.
6. The control chip according to any one of claims 1 to 5, wherein when the control chip is connected to the flyback switching power supply circuit, the second input terminal VCC is connected to a ground terminal of the control chip through a first capacitor; when the control chip is connected to the buck switching power supply circuit, the second input terminal VCC is connected to the ground terminal of the control chip through the second capacitor.
7. The control chip according to claim 6, wherein the control chip comprises a high voltage start circuit, an input terminal of the high voltage start circuit is connected to the power input terminal, an output terminal of the high voltage start circuit is connected to the second input terminal VCC, and the high voltage start circuit is configured to charge a second capacitor of the second input terminal VCC when the system is powered on, so that the control chip is normally started.
8. The control chip according to claim 1, wherein the control chip further comprises an oscillation circuit, an input terminal of the oscillation circuit is connected to an output terminal of the feedback voltage detection module, an output terminal of the oscillation circuit is connected to the PWM module, the oscillation circuit is configured to generate an operating frequency of the switching power supply circuit, and the PWM module adjusts a frequency of the power switching signal according to the operating frequency.
9. The control chip according to claim 1, wherein the control chip comprises a protection module, the protection module is connected to the PWM module, and the protection module is configured to send a signal to the PWM module when a system abnormality is detected, and turn off the power switching tube through the PWM module.
10. The control chip according to claim 1, wherein the control chip further comprises a driving circuit, a driving signal output end of the driving circuit is connected to a control end of a power switch tube, the power switch tube is connected in series in a power loop of a switching power circuit, an input end of the driving circuit is connected to a PWM signal output end of the PWM module, the driving circuit is configured to convert the power switch signal into the driving signal to control on/off of the power switch tube, and the power switch tube is integrated in the control chip or serves as a peripheral circuit of the control chip.
11. The control chip according to any one of claims 7 to 10, wherein the control chip is packaged in a dual in-line package or in a chip IC package.
12. The control chip of claim 11, wherein the control chip is provided with a plurality of pins, including: the high-voltage starting circuit comprises a grounding terminal pin, a first detection voltage input pin, a second detection voltage input pin and a high-voltage starting signal input pin.
13. A switching power supply circuit comprises a Buck power supply or a Flyback power supply, and is characterized by further comprising a control chip according to any one of claims 1-12, wherein the control chip is connected with a Buck switching power supply peripheral circuit to form a Buck switching power supply; the control chip is connected with the Flyback switching power supply peripheral circuit to form a Flyback switching power supply circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120366156.7U CN214626787U (en) | 2021-02-08 | 2021-02-08 | Switching power supply circuit and control chip applied to switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120366156.7U CN214626787U (en) | 2021-02-08 | 2021-02-08 | Switching power supply circuit and control chip applied to switching power supply |
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| Publication Number | Publication Date |
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| CN214626787U true CN214626787U (en) | 2021-11-05 |
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| CN202120366156.7U Active CN214626787U (en) | 2021-02-08 | 2021-02-08 | Switching power supply circuit and control chip applied to switching power supply |
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| CN (1) | CN214626787U (en) |
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