CN113271001B - Power management chip, switch power management system and method - Google Patents
Power management chip, switch power management system and method Download PDFInfo
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- CN113271001B CN113271001B CN202110500572.6A CN202110500572A CN113271001B CN 113271001 B CN113271001 B CN 113271001B CN 202110500572 A CN202110500572 A CN 202110500572A CN 113271001 B CN113271001 B CN 113271001B
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Abstract
The invention provides a power management chip, a switch power management system and a method, wherein the power management chip comprises a VCC charging circuit, an undervoltage protection detection module and a function control logic module; the high-voltage end is connected to the power end through a VCC charging circuit, and the VCC charging circuit is used for charging a capacitor Cvcc externally connected with the power management chip when the power management chip is electrified; the power end is connected to the resistor divider circuit; the sampling end of the resistor voltage dividing circuit is respectively connected to the input ends of the undervoltage protection detection module and the alternating current power-off detection module, the output ends of the undervoltage protection detection module and the alternating current power-off detection module are respectively connected to the functional control logic module, the pulse output end of the functional control logic module is connected to the VCC charging circuit, and the output end of the functional control logic module is connected to the driving end. The power management chip reduces the loss of the switching power supply and improves the efficiency of the switching power supply.
Description
Technical Field
The invention belongs to the technical field of switching power supplies, and particularly relates to a power supply management chip, a switching power supply management system and a switching power supply management method.
Background
In the current switching power supply system, the power management chip is started by charging a capacitor connected with a power pin in the power management chip by connecting a resistor after AC rectification. The detection of the undervoltage protection Brownout of the input alternating current in the switching power supply system is also realized directly through resistance voltage division. The switching power supply system has Xcap capacitors with a filtering function at an alternating-current end, a large amount of charges exist when alternating current is disconnected, and timely discharging is needed, but the discharging of the Xcap capacitors is realized by connecting resistors in parallel on the Xcap capacitors. Therefore, when the conventional switching power supply system works normally, the chip starting resistor, the undervoltage protection Brownout detection of the input alternating voltage and the resistor connected in parallel with xcap all generate larger loss, and the market requirement of pursuing low standby power consumption at present cannot be met.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a power supply management chip, a switching power supply management system and a switching power supply management method, which can reduce the loss of a switching power supply and improve the efficiency of the switching power supply.
In a first aspect, a power management chip includes a pin including a power terminal, a driving terminal, and a high voltage terminal; the power management chip comprises an undervoltage protection detection module and a function control logic module; the power management chip also comprises a VCC charging circuit, a resistor voltage dividing circuit and an alternating current power-off detection module;
The high-voltage end is connected to the power end through a VCC charging circuit, and the VCC charging circuit is used for charging a capacitor Cvcc externally connected with the power management chip when the power management chip is electrified;
the power end is connected to the resistor divider circuit; the sampling end of the resistor voltage dividing circuit is respectively connected to the input ends of the undervoltage protection detection module and the alternating current power-off detection module, the output ends of the undervoltage protection detection module and the alternating current power-off detection module are respectively connected to the functional control logic module, the pulse output end of the functional control logic module is connected to the VCC charging circuit, and the output end of the functional control logic module is connected to the driving end.
Preferably, the VCC charging circuit includes a power tube M1 and a power tube NJFET;
the drain electrode of the power tube M1 is respectively connected to the high-voltage end and the drain electrode of the power tube NJFET, the grid electrode of the power tube NJFET is grounded, the grid electrode of the power tube M1 is connected to the pulse output end of the functional control logic module, and the source electrode of the power tube NJFET is connected to the pulse output end of the functional control logic module through a resistor R3; the source electrode of the power tube M1 is connected to the power supply end sequentially through a resistor R1 and a positive connection first diode.
Preferably, the resistor divider circuit comprises a power tube M2; the source electrode of the power tube M2 is grounded through a resistor R2, and the drain electrode of the power tube M2 is connected to the anode of the first diode; the drain electrode of the power tube M2 is used as the sampling end, and the grid electrode of the power tube M2 is connected to the function control logic module.
Preferably, the under-voltage protection detection module is used for detecting whether the sampling voltage output by the sampling end in the resistor voltage dividing circuit is greater than a preset under-voltage detection voltage threshold value after being started; if yes, judging that the power management chip works normally; if not, judging that the power management chip does not work;
the function control logic module is used for generating a driving signal to be transmitted to the driving end when the power management chip works normally;
the alternating current power-off detection module is used for detecting whether the sampling voltage is cut off in a preset time after being started; if so, triggering the XCAP capacitor externally connected with the power management chip to discharge.
Preferably, the power management chip further comprises a counter connected with the function control logic module;
The under-voltage protection detection module is specifically configured to start a counter to start timing when detecting that the sampling voltage is smaller than the under-voltage detection voltage threshold; whether the sampling voltage is larger than the undervoltage detection voltage threshold value is detected in a preset timing period or not, and if so, resetting a counter; if not, the power management chip is judged to be not working.
Preferably, the power management chip further comprises a chip initialization module;
The input end of the chip initialization module is connected with the power end, and the output end of the chip initialization module is connected with the function control logic module.
In a second aspect, a switch management system includes a power module, an output module, and the power management chip of the first aspect;
The power module comprises an AC power supply and the XCAP capacitor, and is connected to a high-voltage end and a power end of the power management chip; the driving end of the power management chip is connected to the output module.
Preferably, the power module further comprises a rectifier bridge, a main coil Lp and an auxiliary coil Laux;
Wherein the auxiliary coil Laux is coupled with the main coil Lp; the AC power supply is connected to the input end of the rectifier bridge through the XCAP capacitor, the output end of the rectifier bridge is grounded through a capacitor C1, the output end of the rectifier bridge is also connected to the main coil Lp, and the high-voltage end of the power management chip is connected to the input end of the rectifier bridge through a resistor RHV and two second diodes which are reversely connected;
The power supply end of the power supply management chip is grounded through the third diode and the auxiliary coil Laux which are connected in turn, and the power supply end of the power supply management chip is grounded through the capacitor Cvcc.
Preferably, the output module comprises a secondary coil Ls and a power tube M0;
Wherein the secondary coil Ls is coupled with the primary coil Lp, and the output of the secondary coil Ls is used as the output of the switch management system; the driving end of the power management chip is connected with the grid electrode of the power tube M0, the drain electrode of the power tube M0 is connected to the main coil Lp, and the source electrode of the power tube M0 is grounded through the resistor RCS.
In a third aspect, a switching power supply management method is applied to the switching management system in the first aspect, and the method includes:
when the power management chip is electrified, charging a capacitor Cvcc in the switch management system;
when the power management chip is started, the power management chip generates a periodic pulse signal to control the internal VCC charging circuit to conduct periodically, so that the internal under-voltage protection detection module and the internal alternating current power-off detection module are started periodically;
After the undervoltage protection detection module is started, detecting whether the sampling voltage output by the resistor voltage dividing circuit is greater than a preset undervoltage detection voltage threshold value or not; if yes, judging that the power management chip works normally; if not, judging that the power management chip does not work;
After the alternating current power-off detection module is started, detecting whether the sampling voltage is cut off or not in a preset time; if so, triggering the XCAP capacitor externally connected with the power management chip to discharge.
Preferably, after the undervoltage protection detection module determines that the power management chip works normally, the method further comprises:
when the undervoltage protection detection module detects that the sampling voltage is smaller than the undervoltage detection voltage threshold value, starting a counter inside a power management chip to start timing;
The under-voltage protection detection module detects whether the sampling voltage is larger than the threshold value of the under-voltage detection voltage in a preset timing period, and if so, the counter is cleared; if not, judging that the power management chip does not work;
after the alternating current power-off detection module is started, detecting whether the sampling voltage changes along with the AC power supply in a preset time;
And if not, judging that the sampling voltage is cut off, triggering the XCAP capacitor to discharge until the voltage on the XCAP capacitor is lower than a preset cut-off protection threshold.
According to the technical scheme, the power management chip, the switch power management system and the method provided by the invention integrate three functions of switch power starting, input alternating voltage undervoltage detection and XCAP capacitor discharging into one pin to realize, reduce the loss of the switch power and improve the efficiency of the switch power.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. Like elements or portions are generally identified by like reference numerals throughout the several figures. In the drawings, elements or portions thereof are not necessarily drawn to scale.
Fig. 1 is a circuit diagram of a power management chip according to an embodiment of the invention.
Fig. 2 is a circuit diagram of a switch sample-and-hold circuit according to an embodiment of the invention.
Fig. 3 is a circuit diagram of a pulse generating circuit according to an embodiment of the invention.
Fig. 4 is a flowchart of a switching power supply management method according to a third embodiment of the present invention.
Detailed Description
Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application. It is noted that unless otherwise indicated, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs.
It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
As used in this specification and the appended claims, the term "if" may be interpreted as "when..once" or "in response to a determination" or "in response to detection" depending on the context. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".
Embodiment one:
referring to fig. 1, a power management chip includes pins including a power supply terminal, a driving terminal, and a high voltage terminal; the power management chip comprises an undervoltage protection detection module, a function control logic module, a VCC charging circuit, a resistor voltage division circuit and an alternating current power-off detection module;
The high-voltage end is connected to the power end through a VCC charging circuit, and the VCC charging circuit is used for charging a capacitor Cvcc externally connected with the power management chip when the power management chip is electrified;
the power end is connected to the resistor divider circuit; the sampling end of the resistor voltage dividing circuit is respectively connected to the input ends of the undervoltage protection detection module and the alternating current power-off detection module, the output ends of the undervoltage protection detection module and the alternating current power-off detection module are respectively connected to the functional control logic module, the pulse output end of the functional control logic module is connected to the VCC charging circuit, and the output end of the functional control logic module is connected to the driving end.
Preferably, the power management chip further comprises a chip initialization module;
The input end of the chip initialization module is connected with the power end, and the output end of the chip initialization module is connected with the function control logic module.
Specifically, the power management chip transmits the sampling voltage output by the sampling end of the resistor divider circuit to the alternating current power-off detection module and the undervoltage protection detection module, the 2 modules generate detection judgment signals and transmit the detection judgment signals to the functional control logic module, and the functional control logic module generates periodic pulse signals to periodically start the alternating current power-off detection module and the undervoltage protection detection module, so that the power consumption of the circuit is almost zero when the 2 modules are not started and are not detected. The power management chip reduces the loss of the switching power supply and improves the efficiency of the switching power supply.
Preferably, the VCC charging circuit includes a power tube M1 and a power tube NJFET;
the drain electrode of the power tube M1 is respectively connected to the high-voltage end and the drain electrode of the power tube NJFET, the grid electrode of the power tube NJFET is grounded, the grid electrode of the power tube M1 is connected to the pulse output end of the functional control logic module, and the source electrode of the power tube NJFET is connected to the pulse output end of the functional control logic module through a resistor R3; the source electrode of the power tube M1 is connected to the power supply end sequentially through a resistor R1 and a positive connection first diode.
Preferably, the resistor divider circuit comprises a power tube M2; the source electrode of the power tube M2 is grounded through a resistor R2, and the drain electrode of the power tube M2 is connected to the anode of the first diode; the drain electrode of the power tube M2 is used as the sampling end, and the grid electrode of the power tube M2 is connected to the function control logic module.
Specifically, the power management chip is internally connected through an ultrahigh voltage power tube M1, a resistor R2 and a power tube M2 to form a BO detection (namely under-voltage protection detection) resistor string, and the power tubes M1 and M2 are conducted to form an alternating current power supply to ground electric string. The high voltage terminal HV is further connected to the power transistor NJFET, and when the power terminal VCC is charged, the S gate bias voltage of the power transistor M1 is provided, and the resistor R3 is a current limiting resistor.
After the power management chip is electrified, the power tube M1 is conducted to charge the power end VCC, and when the voltage of the power end rises to exceed the starting threshold voltage VCC_ON, the power management chip is started. Most of the modules of the power management chip are not operated before that, and the power tube M2 is also turned off. After the power management chip is started, the chip initialization module initializes, and the function control logic module outputs a signal to close the power tube M1, so that the power end VCC is closed to charge, the power consumption of the power management chip after the power management chip is started is saved, and the power management chip is powered by the capacitor Cvcc. And then the function control logic module outputs a periodic narrow pulse signal to the resistor divider circuit, the power tube M1 and the power tube M2 are periodically conducted, and the on-resistance of the power tubes M1 and M2 is much smaller than that of the resistors RHV, R1 and R2 and can be ignored.
The embodiment adopts a mode of combining the power tube NJFET and the ultrahigh voltage switch tube, can realize the starting of VCC charging, and closes the VCC charging after the starting, so that power consumption can be hardly generated.
Preferably, the under-voltage protection detection module is used for detecting whether the sampling voltage output by the sampling end in the resistor voltage dividing circuit is greater than a preset under-voltage detection voltage threshold value after being started; if yes, judging that the power management chip works normally; if not, judging that the power management chip does not work;
the function control logic module is used for generating a driving signal to be transmitted to the driving end when the power management chip works normally;
the alternating current power-off detection module is used for detecting whether the sampling voltage is cut off in a preset time after being started; if so, triggering the XCAP capacitor externally connected with the power management chip to discharge.
Specifically, when the under-voltage protection detection module detects that the sampling voltage is greater than the under-voltage detection voltage threshold, the power management chip is judged to work normally, and the function control logic module outputs a normal driving signal to the driving end DRV to control the power tube. The energy of the main coil Lp can be transmitted to the secondary coil Ls and the auxiliary coil Laux to supply power to the direct current output and the power supply end VCC respectively, otherwise, the driving end DRV always outputs a low level to turn off the power tube.
The alternating current power-off detection module detects whether the sampling voltage is cut off, if the cut off triggers the capacitor XCAP to discharge, the function control logic module always conducts the power tube M1 and the power tube M2 at the moment to form a passage of the capacitor XCAP to the ground, and the sampling voltage is much lower than VCC because the resistance RHV is far greater than the resistances R1 and R2, and the VCC cannot be charged. Meanwhile, as the power management chip is in normal operation, the charge on the capacitor Cvcc is consumed, VCC is reduced until VCC is smaller than the cutoff protection threshold VCC_OFF, at the moment, the power management chip is reset, the power tube M2 is closed, and the VCC is charged again, and the above processes are repeated.
Preferably, the power management chip further comprises a counter connected with the function control logic module;
The under-voltage protection detection module is specifically configured to start a counter to start timing when detecting that the sampling voltage is smaller than the under-voltage detection voltage threshold; whether the sampling voltage is larger than the undervoltage detection voltage threshold value is detected in a preset timing period or not, and if so, resetting a counter; if not, the power management chip is judged to be not working.
Specifically, after the power management chip works normally, if the sampling voltage < undervoltage detection voltage threshold occurs, the counter starts to count, and when the sampling voltage > undervoltage detection voltage threshold exists in the period of ending the counting, the counter is cleared, otherwise, the time of the sampling voltage < BO threshold exceeds the preset counting period, and the power management chip does not work.
When the sampling voltage keeps unchanged and exceeds the timing time, the power management chip multiplexes the resistor divider circuit or the VCC charging circuit to discharge the capacitor XCAP, and 2 conditions for stopping the discharge of the capacitor XCAP are as follows: 1. when the chip works normally, the voltage on the capacitor XCAP is reduced to a lower threshold voltage by the multiplexing resistor divider circuit, and the discharging is stopped. 2. The sampling voltage is less than the undervoltage detection voltage threshold, namely, the power management chip can start VCC charging to discharge the capacitor XCAP after undervoltage protection, and the capacitor XCAP can be ensured to discharge to a very low voltage through the 2 conditions.
In summary, the power management chip integrates three functions of starting a switching power supply, detecting under-voltage of input alternating voltage and discharging XCAP capacitor into one pin to realize, so that the loss of the switching power supply is reduced, and the efficiency of the switching power supply is improved.
In addition, the embodiment also provides a circuit diagram of the alternating current power-off detection module and the undervoltage protection detection module.
Fig. 2 is a sample-and-hold circuit of switches in an ac power down detection module and an under-voltage protection detection module. The switch sampling hold circuit comprises a switch tube, a sampling capacitor and a comparator, wherein the sampling end of the resistor voltage dividing circuit is connected with the source electrode of the switch tube, the grid electrode of the switch tube is connected with the function control logic module, the drain electrode of the switch tube is grounded through the sampling capacitor, the drain electrode of the switch tube is also connected with the forward input end of the comparator, the reverse input end of the comparator is connected with the reference voltage, and the output end of the comparator outputs a judging result.
The circuit of fig. 2 is used for controlling the switch to be periodically turned on, transmitting the sampling voltage to the sampling capacitor and maintaining the sampling voltage, comparing the sampling voltage with a preset reference voltage through a comparator to realize a corresponding detection function, for example, setting the reference voltage as an undervoltage detection voltage threshold value, comparing the reference voltage with the sampling voltage, outputting an undervoltage protection judgment signal, timing through a counter, and outputting an undervoltage protection trigger signal.
Fig. 3 is a pulse generation circuit in an ac power down detection module and an under-voltage protection detection module. The pulse generating circuit comprises an AND gate, an NOT gate and a delay capacitor. The output end of the comparator in the switch sample hold circuit is connected with the input end of the NOT gate and one input end of the AND gate, the output end of the NOT gate is connected with the other input end of the AND gate, the output end of the NOT gate is grounded through a delay capacitor, and the output end of the AND gate is used as the output of the pulse generating circuit.
The pulse generating circuit may perform AC power down detection, for example, resetting a reference voltage for the comparator of fig. 2, and the comparator output is connected to the pulse generating circuit, so that the output periodic pulse signal resets the counter because the sampling voltage varies with the AC power source, thus not triggering an AC power down event. If the current is cut off, no periodic pulse signal is generated until the counter times out, and a current cutting event is triggered, so that the XCAP capacitor is discharged.
Embodiment two:
A switch management system comprises a power supply module, an output module and the power supply management chip;
the power module comprises an AC power supply and an XCAP capacitor, and is connected to the high-voltage end and the power end of the power management chip; the driving end of the power management chip is connected to the output module.
Preferably, the power module further comprises a rectifier bridge, a main coil Lp and an auxiliary coil Laux;
Wherein the auxiliary coil Laux is coupled with the main coil Lp; the AC power supply is connected to the input end of the rectifier bridge through the XCAP capacitor, the output end of the rectifier bridge is grounded through a capacitor C1, the output end of the rectifier bridge is also connected to the main coil Lp, and the high-voltage end of the power management chip is connected to the input end of the rectifier bridge through a resistor RHV and two second diodes which are reversely connected;
The power supply end of the power supply management chip is grounded through the third diode and the auxiliary coil Laux which are connected in turn, and the power supply end of the power supply management chip is grounded through the capacitor Cvcc.
Specifically, the AC power passes through the rectifying bridge filter capacitor C1 and one end of the main coil Lp. The AC power supply is connected in parallel with the XCAP capacitor and there is a large amount of charge after the switch is turned off. The high voltage end HV of the power management chip is connected with an AC power supply through a resistor RHV and two second diodes. The power supply end of the power supply management chip is also connected with a large capacitor Cvcc and is connected with the auxiliary coil Laux through a third diode.
Preferably, the output module comprises a secondary coil Ls and a power tube M0;
Wherein the secondary coil Ls is coupled with the primary coil Lp, and the output of the secondary coil Ls is used as the output of the switch management system; the driving end of the power management chip is connected with the grid electrode of the power tube M0, the drain electrode of the power tube M0 is connected to the main coil Lp, and the source electrode of the power tube M0 is grounded through the resistor RCS.
Specifically, the driving end DRV of the power management chip is connected to the gate of the power tube M0, the source of the power tube M0 is connected to the current limiting resistor RCS to ground, and the drain of the power tube M0 is connected to one end of the main coil Lp. The secondary coil Ls is coupled to the primary coil Lp to form the output of the switch management system.
For a brief description of the system provided by the embodiments of the present invention, reference may be made to the corresponding content in the foregoing embodiments where the description of the embodiments is not mentioned.
Embodiment III:
A switching power supply management method, see fig. 4, applied to a system including the above switch management system, the method includes:
when the power management chip is electrified, charging a capacitor Cvcc in the switch management system;
when the power management chip is started, the power management chip generates a periodic pulse signal to control the internal VCC charging circuit to conduct periodically, so that the internal under-voltage protection detection module and the internal alternating current power-off detection module are started periodically;
After the undervoltage protection detection module is started, detecting whether the sampling voltage output by the resistor voltage dividing circuit is greater than a preset undervoltage detection voltage threshold value or not; if yes, judging that the power management chip works normally; if not, judging that the power management chip does not work;
After the alternating current power-off detection module is started, detecting whether the sampling voltage is cut off or not in a preset time; if so, triggering the XCAP capacitor externally connected with the power management chip to discharge.
Preferably, after the undervoltage protection detection module determines that the power management chip works normally, the method further comprises:
when the undervoltage protection detection module detects that the sampling voltage is smaller than the undervoltage detection voltage threshold value, starting a counter inside a power management chip to start timing;
The under-voltage protection detection module detects whether the sampling voltage is larger than the threshold value of the under-voltage detection voltage in a preset timing period, and if so, the counter is cleared; if not, judging that the power management chip does not work;
after the alternating current power-off detection module is started, detecting whether the sampling voltage changes along with the AC power supply in a preset time;
And if not, judging that the sampling voltage is cut off, triggering the XCAP capacitor to discharge until the voltage on the XCAP capacitor is lower than a preset cut-off protection threshold.
Preferably, before the power management chip is started, the method further comprises:
charging a power supply end of a power supply management chip by adopting the AC power supply;
When the voltage of the power supply end in the power supply management chip exceeds a preset starting threshold value, the power supply management chip is started to stop charging the power supply end by adopting the AC power supply.
For a brief description of the method provided by the embodiments of the present invention, reference may be made to the corresponding content in the foregoing embodiments where the description of the embodiments is not mentioned.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention, and are intended to be included within the scope of the appended claims and description.
Claims (6)
1. The pin of the power management chip comprises a power end, a driving end and a high-voltage end; the power management chip comprises an undervoltage protection detection module and a function control logic module; the power management chip is characterized by further comprising a VCC charging circuit, a resistor voltage dividing circuit and an alternating current power-off detection module;
The high-voltage end is connected to the power end through a VCC charging circuit, and the VCC charging circuit is used for charging a capacitor Cvcc externally connected with the power management chip when the power management chip is electrified;
the power end is connected to the resistor divider circuit; the sampling end of the resistor voltage dividing circuit is respectively connected to the input ends of the undervoltage protection detection module and the alternating current power-off detection module, the output ends of the undervoltage protection detection module and the alternating current power-off detection module are respectively connected to the function control logic module, the pulse output end of the function control logic module is connected to the VCC charging circuit, and the output end of the function control logic module is connected to the driving end;
The VCC charging circuit comprises a power tube M1 and a power tube NJFET;
The drain electrode of the power tube M1 is respectively connected to the high-voltage end and the drain electrode of the power tube NJFET, the grid electrode of the power tube NJFET is grounded, the grid electrode of the power tube M1 is connected to the pulse output end of the functional control logic module, and the source electrode of the power tube NJFET is connected to the pulse output end of the functional control logic module through a resistor R3; the source electrode of the power tube M1 is connected to the power supply end sequentially through a resistor R1 and a positive connection first diode;
The resistor voltage dividing circuit comprises a power tube M2; the source electrode of the power tube M2 is grounded through a resistor R2, and the drain electrode of the power tube M2 is connected to the anode of the first diode; the drain electrode of the power tube M2 is used as the sampling end, and the grid electrode of the power tube M2 is connected to the function control logic module;
The under-voltage protection detection module is used for detecting whether the sampling voltage output by the sampling end in the resistor voltage dividing circuit is larger than a preset under-voltage detection voltage threshold value or not after the under-voltage protection detection module is started; if yes, judging that the power management chip works normally; if not, judging that the power management chip does not work;
the function control logic module is used for generating a driving signal to be transmitted to the driving end when the power management chip works normally;
the alternating current power-off detection module is used for detecting whether the sampling voltage is cut off in a preset time after being started; if yes, triggering the XCAP capacitor externally connected with the power management chip to discharge;
The power management chip further comprises a counter connected with the function control logic module;
The under-voltage protection detection module is specifically configured to start a counter to start timing when detecting that the sampling voltage is smaller than the under-voltage detection voltage threshold; whether the sampling voltage is larger than the undervoltage detection voltage threshold value is detected in a preset timing period or not, and if so, resetting a counter; if not, judging that the power management chip does not work;
The power management chip further comprises a chip initialization module;
The input end of the chip initialization module is connected with the power end, and the output end of the chip initialization module is connected with the function control logic module.
2. A switch management system comprising a power module, an output module, and the power management chip of claim 1;
the power module comprises an AC power supply and an XCAP capacitor, and is connected to the high-voltage end and the power end of the power management chip; the driving end of the power management chip is connected to the output module.
3. The switch management system of claim 2, wherein,
The power supply module further comprises a rectifier bridge, a main coil Lp and an auxiliary coil Laux;
Wherein the auxiliary coil Laux is coupled with the main coil Lp; the AC power supply is connected to the input end of the rectifier bridge through the XCAP capacitor, the output end of the rectifier bridge is grounded through a capacitor C1, the output end of the rectifier bridge is also connected to the main coil Lp, and the high-voltage end of the power management chip is connected to the input end of the rectifier bridge through a resistor RHV and two second diodes which are reversely connected;
The power supply end of the power supply management chip is grounded through the third diode and the auxiliary coil Laux which are connected in turn, and the power supply end of the power supply management chip is grounded through the capacitor Cvcc.
4. The switch management system of claim 2, wherein,
The output module comprises a secondary coil Ls and a power tube M0;
Wherein the secondary coil Ls is coupled with the primary coil Lp, and the output of the secondary coil Ls is used as the output of the switch management system; the driving end of the power management chip is connected with the grid electrode of the power tube M0, the drain electrode of the power tube M0 is connected to the main coil Lp, and the source electrode of the power tube M0 is grounded through the resistor RCS.
5. A switching power supply management method applied to the switching management system of claim 2, the method comprising:
when the power management chip is electrified, charging a capacitor Cvcc in the switch management system;
when the power management chip is started, the power management chip generates a periodic pulse signal to control the internal VCC charging circuit to conduct periodically, so that the internal under-voltage protection detection module and the internal alternating current power-off detection module are started periodically;
After the undervoltage protection detection module is started, detecting whether the sampling voltage output by the resistor voltage dividing circuit is greater than a preset undervoltage detection voltage threshold value or not; if yes, judging that the power management chip works normally; if not, judging that the power management chip does not work;
After the alternating current power-off detection module is started, detecting whether the sampling voltage is cut off or not in a preset time; if so, triggering the XCAP capacitor externally connected with the power management chip to discharge.
6. The method of claim 5, further comprising, after the undervoltage protection detection module determines that the power management chip is operating properly:
when the undervoltage protection detection module detects that the sampling voltage is smaller than the undervoltage detection voltage threshold value, starting a counter inside a power management chip to start timing;
The under-voltage protection detection module detects whether the sampling voltage is larger than the threshold value of the under-voltage detection voltage in a preset timing period, and if so, the counter is cleared; if not, judging that the power management chip does not work;
After the alternating current power-off detection module is started, detecting whether the sampling voltage changes along with the AC power supply in a preset time; and if not, judging that the sampling voltage is cut off, triggering the XCAP capacitor to discharge until the voltage on the XCAP capacitor is lower than a preset cut-off protection threshold.
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