CN113541462A

CN113541462A - High-voltage starting circuit and switching power supply circuit

Info

Publication number: CN113541462A
Application number: CN202010314039.6A
Authority: CN
Inventors: 施国民; 雷晗; 夏云凯
Original assignee: Xi'an Dingxin Microelectronic Co ltd
Current assignee: Xi'an Dingxin Microelectronic Co ltd
Priority date: 2020-04-20
Filing date: 2020-04-20
Publication date: 2021-10-22

Abstract

The application discloses high-voltage starting circuit and switching power supply circuit. The high-voltage starting circuit (10) is used for providing current for a chip in a switching power supply when the switching power supply is started, and comprises a current input end (110) and a current output end (120), wherein the current input end (110) is configured to receive high-voltage current, and the current output end (120) is configured to provide output current for the chip, and the high-voltage starting circuit further comprises: a control signal input (130) configured to receive a control signal; and the switching circuit module (140) is arranged on a current path between the current input end (110) and the current output end (120), is connected with the control signal input end (130), and is configured to break the current path from the current input end (110) to the current output end (120) according to the received control signal.

Description

High-voltage starting circuit and switching power supply circuit

Technical Field

The present application relates to the field of power supply starting technologies, and in particular, to a high voltage starting circuit and a switching power supply circuit.

Background

Switching power supply circuits typically include high voltage start-up techniques. Before the power supply works normally, the power supply cannot be supplied with power by the auxiliary winding, and the chip is started by the high-voltage starting circuit when the power supply is electrified, so that the power supply is started to work normally. After the power supply works normally, the chip power supply is changed from a high-voltage starting circuit to be provided by the auxiliary winding. The conventional high-voltage start-up circuit is shown in fig. 5, and a large resistor in the order of mega-ohms is connected between the input power and the chip to supply a current to complete the start-up of the chip. However, the large resistor causes unnecessary power consumption waste after the starting process of the switching power supply circuit is finished; and the traditional high-voltage starting circuit also does not provide protection when the power supply end of the chip is short-circuited to the ground, so that the current is limited, and after the VDD is short-circuited to the ground, the high-voltage starting circuit can be burnt due to the long-time working of large current.

Aiming at the technical problems that the existing high-voltage starting circuit in the prior art uses large resistor to waste power consumption greatly, and the existing high-voltage starting circuit has no short-circuit protection measure and is easy to burn out when the high-voltage starting circuit is short-circuited, an effective solution is not provided at present.

Disclosure of Invention

The utility model provides a high-voltage starting circuit and switching power supply circuit to at least, solve the current high-voltage starting circuit who exists among the prior art and use the very big extravagant consumption of big resistance, and do not have short-circuit protection measure among the current high-voltage starting circuit, the technical problem who is burnt easily when the short circuit of high-voltage starting circuit.

According to an aspect of the present application, there is provided a high voltage start-up circuit for supplying current to a chip in a switching power supply when the switching power supply is started up, the high voltage start-up circuit including a current input terminal and a current output terminal, wherein the current input terminal is configured to receive high voltage current, and the current output terminal is configured to supply output current to the chip, the high voltage start-up circuit further including: a control signal input configured to receive a control signal; and the switch circuit module is arranged on a current path between the current input end and the current output end, is connected with the control signal input end, and is configured to disconnect the current path from the current input end to the current output end according to the received control signal.

According to another aspect of the present application, there is provided a high voltage start-up circuit for supplying current to a chip in a switching power supply when the switching power supply is started up, including a current input terminal and a current output terminal, wherein the current input terminal is configured to receive high voltage current, and the current output terminal is configured to supply output current to the chip, further including: and the current setting circuit is arranged on a current path between the current input end and the current output end, and is used for receiving input current from the current input end and providing output current for the current output end according to the voltage of the current output end.

According to another aspect of the present application, there is provided a switching power supply circuit, including a rectifier, a chip, and a high voltage start circuit disposed between the rectifier and the chip, the high voltage start circuit including a current input terminal and a current output terminal, wherein the current input terminal is configured to receive a high voltage current, and the current output terminal is configured to provide an output current to the chip, further including: a control signal input configured to receive a control signal; and the switch circuit module is arranged on a current path between the current input end and the current output end, is connected with the control signal input end, and is configured to disconnect the current path from the current input end to the current output end according to the received control signal.

Therefore, the power switch circuit and the high-voltage starting circuit provided by the embodiment of the application are arranged between the rectifier and the chip. The high-voltage starting circuit is connected with the rectifier so as to control the on, off and magnitude of the starting current.

And the high voltage start-up circuit includes a current input and a current output, wherein the current input is configured to receive the high voltage current from the rectifier. The current output is configured to provide an output current to the chip. And the high voltage start-up circuit further comprises: and the control signal input end sends a control signal to the switch circuit module through the control signal input end.

The high-voltage starting circuit further comprises a switch circuit module, which is arranged on a current path between the current input end and the current output end, is connected with the control signal input end, and is configured to disconnect the current path from the current input end to the current output end according to the received control signal. Therefore, under the condition that the chip in the high-voltage starting circuit is charged, the effect of timely disconnecting the circuit is achieved, and unnecessary loss is avoided.

The high voltage start-up circuit also includes a current setting circuit connected to the switching circuit module and the current output terminal and configured to receive an input current from the switching circuit module. And the power supply circuit is connected with the chip through the current output end, so that the voltage of the current output end is monitored in real time, the monitored voltage of the current output end is compared with a preset large current threshold, and whether the power supply current is a preset large current value or a small current value is set according to a comparison result. And when the high-voltage starting circuit is short-circuited, a small current value is set through the current setting circuit, so that the high-voltage starting circuit is prevented from being burnt.

And then solved the current high-voltage starting circuit that exists among the prior art and used the very big extravagant consumption of big resistance to there is not short-circuit protection measure in the current high-voltage starting circuit, the technical problem that is burnt out easily when the short circuit of high-voltage starting circuit.

The above and other objects, advantages and features of the present application will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the present application will be described in detail hereinafter by way of illustration and not limitation with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

fig. 1 is a circuit schematic diagram of a switching power supply circuit according to an embodiment of the present application;

FIG. 2 is a circuit schematic of the high voltage start-up circuit of FIG. 1;

FIG. 3 is yet another circuit schematic of the high voltage start-up circuit of FIG. 1;

FIG. 4 is a waveform schematic diagram of a high voltage start-up circuit according to an embodiment of the present application; and

fig. 5 is a schematic diagram of a conventional high voltage start-up circuit.

Detailed Description

It should be noted that, in the present disclosure, the embodiments and features of the embodiments may be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

In order to make the technical solutions of the present disclosure better understood by those skilled in the art, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only some embodiments of the present disclosure, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

It should be noted that the terms "first," "second," and the like in the description and claims of the present disclosure and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances for describing the embodiments of the disclosure herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

Fig. 1 is a circuit schematic diagram of a switching power supply circuit 20 according to an embodiment of the present application, and referring to fig. 1, the switching power supply circuit 20 includes a rectifier 210, a chip 220, and a high-voltage start circuit 10 disposed between the rectifier 210 and the chip 220, where the high-voltage start circuit 10 includes a current input terminal 110 and a current output terminal 120, where the current input terminal 110 is configured to receive a high-voltage current, and the current output terminal 120 is configured to provide an output current to the chip, and further includes: a control signal input 130 configured to receive a control signal; the switch circuit module 140 is disposed on a current path between the current input terminal 110 and the current output terminal 120, connected to the control signal input terminal 130, and configured to disconnect the current path from the current input terminal 110 to the current output terminal 120 according to the received control signal.

As described in the background, the conventional high voltage start-up circuit is connected between the input power source and the chip by a large resistor in the order of mega-ohms to provide a current to complete the start-up of the chip. However, the large resistor causes unnecessary power consumption waste after the starting process of the switching power supply circuit is finished; and the traditional high-voltage starting circuit also does not provide protection when the power supply end of the chip is short-circuited to the ground, so that the current is limited, and after the VDD is short-circuited to the ground, the high-voltage starting circuit can be burnt due to the long-time working of large current.

In view of this, the switching power supply circuit 20 according to the present embodiment is provided by disposing the high voltage start circuit 10 between the rectifier 210 and the chip 220. Wherein the high voltage starting circuit 10 controls the on/off and the magnitude of the starting current by connecting with the rectifier 210.

And the high voltage start-up circuit 10 includes a current input 110 and a current output 120, wherein the current input 110 is configured to receive the high voltage current from the rectifier 210. The current output 120 is configured to provide an output current to the chip 220. And the high voltage start-up circuit 10 further comprises: the control signal input terminal 130 is used for sending a control signal from the chip 220 and sending the control signal to the switch circuit module 140 through the control signal input terminal 130.

The high voltage start-up circuit 10 further comprises a switch circuit module 140, disposed in a current path between the current input terminal 110 and the current output terminal 120, and connected to the control signal input terminal 130, and configured to disconnect the current path from the current input terminal 110 to the current output terminal 120 according to the received control signal. Therefore, under the condition that the charging of the chip 220 in the high-voltage starting circuit 10 is completed, the effect of timely disconnecting the circuit is achieved, and unnecessary loss is avoided. And then the technical problem that the high-voltage starting circuit in the prior art uses large resistors to greatly waste power consumption is solved.

In addition, referring to fig. 1, the switching power supply circuit 20 further includes an auxiliary winding unit, and after the power supply normally operates, the power supplied by the chip 220 is changed from the high-voltage starting circuit 10 to the auxiliary winding. The auxiliary winding unit comprises a primary winding NP, a secondary winding NS and an auxiliary winding NA. The Rcs resistor samples the current of the MOSFET for adjusting the on-time of the MOSFET, thereby adjusting the output voltage. The switching power supply circuit 20 further includes a power switch SW (field effect transistor MOSFET), a rectifier diode DS, and a capacitor CS. Further, although not shown in the drawings, the switching power supply circuit 20 further includes an isolation feedback unit.

Optionally, the switching circuit module 140 includes: the switch control circuit 141, the switch control circuit 141 is connected with the control signal input end 130, and is used for generating a switch signal according to the control signal received from the control signal input end 130; and a high voltage switch circuit 142 disposed on a current path from the current input terminal 110 to the current output terminal 120, and connected to the switch control circuit 141, and configured to break the current path from the current input terminal 110 to the current output terminal 120 according to a switching signal received from the switch control circuit 141.

Specifically, referring to fig. 1, the switching circuit module 140 includes a switching control circuit 141 and a high voltage switching circuit 142. The high voltage switch circuit 141 is configured to receive the control signal sent from the control signal input terminal 130, generate a switch signal (e.g., a switch on signal or a switch off signal) according to the control signal, and send the switch signal to the high voltage switch circuit 142. And the high voltage switch circuit 142 may enable or disable the high voltage switch based on the received switch signal. Therefore, after the switching power supply circuit is started, the chip 220 sends out a control signal (for example, a signal that the start has been completed), and the high-voltage switch circuit 141 generates a switch-off signal according to the control signal and sends the switch-off signal to the high-voltage switch circuit 142. After receiving the switch-off signal sent by the high-voltage switch circuit 141, the high-voltage switch circuit 142 turns off the circuit, thereby avoiding power consumption caused by continuous power consumption of the large resistor after the chip 220 finishes power supply when the large resistor is used in the high-voltage circuit 10. Therefore, the technical effect that the circuit is closed after starting and power consumption waste is avoided is achieved.

Optionally, the high voltage start-up circuit 10 further comprises a current setting circuit 150 connected to the switching circuit module 140 and the current output terminal 120, and configured to receive the input current from the switching circuit module 140 and provide the output current to the current output terminal 120 according to the voltage at the current output terminal 120.

Specifically, as described with reference to fig. 1, the high voltage start-up circuit 10 further includes a current setting circuit 150 connected to the switching circuit module 140 and the current output terminal 120, and configured to receive an input current from the switching circuit module 140. And is connected with the chip 220 through the current output terminal 120, thereby monitoring the voltage of the current output terminal 120 in real time, and comparing the monitored voltage of the current output terminal 120 with a preset large current threshold value, and setting whether the supply current is a preset large current value or a small current value according to the comparison result. And when the high voltage starting circuit 10 is short-circuited, a small current value is set by the current setting circuit 150, thereby avoiding burning the high voltage starting circuit. And then solved the current high-voltage starting circuit that exists among the prior art and did not have short-circuit protection measure, the technical problem that is burnt easily when the short circuit of high-voltage starting circuit.

Optionally, the high voltage switching circuit 142 comprises: a first transistor 1421, a second transistor 1422, a first resistor 1423, and a second resistor 1424, wherein a drain of the first transistor 1421 is connected to the current input terminal 110 and a drain of the second transistor 1422, a source of the first transistor 1421 is connected to a source of the second transistor 1422 through the first resistor 1423 and the second resistor 1424, and a gate of the first transistor 1421 is connected to a first end of the first resistor 1423, a source of the second transistor 1422, and the switch control circuit 141; the drain of the second transistor 1422 is connected to the current input terminal 110, the gate of the second transistor 1422 is connected to the first terminal of the first resistor 1423, the first terminal of the second resistor 1424, and the switch control circuit 141, and the source of the second transistor 1422 is connected to the second terminal of the second resistor 1424 and the current setting circuit 150; a first terminal of the first resistor 1423 is connected to the gate of the second transistor 1422, a first terminal of the second resistor 1424, and the switch control circuit 141, and a second terminal of the first resistor 1423 is connected to the source of the first transistor 1421; and a first terminal of the second resistor 1424 is connected to the first terminal of the first resistor 1423, the gate of the second transistor 1422, and the switch control circuit 141, and a second terminal of the second resistor 1424 is connected to the current setting circuit 150.

Specifically, referring to fig. 2, wherein the first transistor 1421 may be a junction field effect transistor or a depletion transistor, and the second transistor 1422 may be a forward-increasing LDMOS transistor. So that the high-voltage switch of the high-voltage starting circuit 10 is turned on or off through the connection mode.

Optionally, referring to fig. 2, the switch control circuit 141 includes a first enhancement NMOS transistor 1411 and a second enhancement NMOS transistor 1412, wherein a drain of the first enhancement NMOS transistor 1411 is connected to a first terminal of a first resistor 1423, a first terminal of a second resistor 1424, and a gate of a second transistor 1422, a source of the first enhancement NMOS transistor 1411 is connected to ground, and a gate of the first enhancement NMOS transistor 1411 is connected to the chip; and the drain of the second enhancement mode NMOS transistor 1412 is connected to the second terminal of the second resistor 1424, the gate of the first transistor 1421, and the source of the second transistor 1422, the source of the second enhancement mode NMOS transistor 1412 is connected to ground, and the gate of the second enhancement mode NMOS transistor 1412 is connected to the chip. Thereby controlling the high voltage switch circuit 141 to be turned on or off through the above connection manner.

Optionally, the current setting circuit 150 includes a voltage monitoring unit 151, a current negative feedback unit 152, a constant current setting unit 153, and a current monitoring unit 154, wherein the voltage monitoring unit 151 is connected to the current output terminal 120 and the constant current setting unit 153, and the voltage monitoring unit 151 is configured to monitor an output voltage of the current output terminal 120 and send the output voltage to the constant current setting unit 153; the current negative feedback unit 152 is connected to the current monitoring unit 154, and the current negative feedback unit 152 is configured to receive the input current monitored by the current monitoring unit 154 and adjust the current of the current setting circuit 150 according to the input current; the constant current setting unit 153 is connected to the voltage monitoring unit 151, and the constant current setting unit 153 is configured to set an input current according to the input voltage sent by the voltage monitoring unit 151; and a current monitoring unit 154 is connected to the current negative feedback unit 152 and the current output terminal 120, and the current monitoring unit 154 is configured to monitor an input current of the chip and send the input current to the current negative feedback unit 152.

Specifically, referring to fig. 1, the voltage monitoring unit 151 detects the output voltage of the current output terminal 120, compares the output voltage with a preset large current value, and transmits the comparison result to the constant current setting unit 153. The constant current setting unit 153 then sets a predetermined current value for the high voltage starting circuit 10 by the comparison result.

Further, the current monitoring unit 154 monitors the output current of the current output terminal 120, and then adjusts the output current value of the current output terminal 120 through the current negative feedback unit 152 so that the output current value is maintained at a constant current value.

Therefore, the voltage and current conditions of the high-voltage starting circuit 10 are monitored in real time by the voltage monitoring unit 151, the current negative feedback unit 152, the constant current setting unit 153 and the current monitoring unit 154 of the current setting circuit 150, and the current in the circuit is further adjusted. And when the high voltage starting circuit 10 is short-circuited, a small current value is set by the current setting circuit 150, thereby avoiding burning the high voltage starting circuit. And then solved the current high-voltage starting circuit that exists among the prior art and did not have short-circuit protection measure, the technical problem that is burnt easily when the short circuit of high-voltage starting circuit.

Optionally, the voltage monitoring unit 151 includes a third enhancement type NMOS transistor 1511, a fourth enhancement type NMOS transistor 1512, and a first diode 1513, wherein a drain of the third enhancement type NMOS transistor 1511 is connected to the constant current setting unit 153, a gate of the third enhancement type NMOS transistor 1511 is connected to the current monitoring unit 154, the current negative feedback unit 152, and an anode of the first diode 1513, and a source of the third enhancement type NMOS transistor 1511 is connected to a drain of the fourth enhancement type NMOS transistor 1512; the drain of the fourth enhancement NMOS tube 1512 is connected to the gate of the fourth enhancement NMOS tube 1512 and the source of the third enhancement NMOS tube 1511, and the source of the fourth enhancement NMOS tube 1512 is connected to ground; and a cathode of the first diode 1513 is connected to the current output terminal 120, and an anode of the first diode 1513 is connected to a drain of the third enhancement type NMOS tube 1511.

Specifically, referring to fig. 2, when the input power is powered on, the voltage value of the chip power supply terminal and the capacitor connected to the chip power supply terminal is 0V, the high voltage starting circuit 20 starts to supply current to the power supply terminal and charge the capacitor CA connected to the power supply terminal, and the voltage monitoring unit 151 starts to monitor the voltage value of the power supply terminal. When the voltage value of the chip power supply terminal and the capacitor connected to the chip power supply terminal is lower than a preset large current threshold value, the current setting circuit 150 sets the start current supplied to the chip 220 and the charging current of the capacitor connected to the chip power supply terminal to a small current value. The high-voltage starting circuit 10 sets a large current threshold for the power supply terminal to be the sum of the thresholds of the third enhanced NMOS transistor 1511 and the fourth enhanced NMOS transistor 1512 minus the PN junction voltage drop of the first diode 1513, where the large current threshold voltage is expressed as:

Vth_IL＝Vth_1512+Vth_1513-Vd_1513

wherein Vth _ IL is a large current threshold voltage, Vth _1512 is a threshold of the third enhancement type NMOS transistor 1511, Vth _1513 is a threshold of the fourth enhancement type NMOS transistor 1512, and Vd _1513 is a PN junction voltage drop of the first diode 1513.

The comparison circuit of the voltage monitoring circuit 151 is completed using a third enhancement type NMOS transistor 1511. The gate of the third enhancement NMOS 1511 is used as one input of the comparator, the source is used as the other input, and the drain is used as the output of the comparator circuit, after the gate-source voltage of the NMOS 1312 is higher than the threshold voltage, the NMOS 1312 turns on, so that the drain voltage is pulled low.

In addition, referring to fig. 3, the comparison function of the third enhancement NMOS 1511 is performed by the comparator 1511, and the power supply terminal is provided with a large current threshold by the reference voltage.

Optionally, the current negative feedback unit 152 includes a fifth enhancement type NMOS transistor 1521 and a sixth enhancement type NMOS transistor 1522, wherein a drain of the fifth enhancement type NMOS transistor 1521 is connected to the gate of the fifth enhancement type NMOS transistor 1521, the gate of the sixth enhancement type NMOS transistor 1522, and the current monitoring unit 154, and a source of the fifth enhancement type NMOS transistor 1521 is connected to ground; the gate of the sixth enhancement NMOS 1522 is connected to the gate of the fifth enhancement NMOS 1521, the drain of the sixth enhancement NMOS 1522 is connected to the gate of the second transistor 1422, the first terminal of the first resistor 1423, the first terminal of the second resistor 1424, and the source of the first enhancement NMOS 1411, and the source of the sixth enhancement NMOS 1522 is connected to ground.

Specifically, referring to fig. 2, the current output from the current monitoring unit 154 to the current negative feedback unit 152 is output to the drain of the fifth enhancement NMOS transistor 1521. When the current flowing out of the high voltage switch circuit 142 increases, the current output by the current monitoring circuit 154 to the fifth enhancement type NMOS transistor 1521 increases, the gate-source voltage of the sixth enhancement type NMOS transistor 1522 increases, the drain-source current flowing into the sixth enhancement type NMOS transistor 1522 increases, the current divided by the sixth enhancement type NMOS transistor 1522 from the first resistor 1423 in the high voltage switch circuit 142 increases, the current flowing through the second resistor 1424 decreases, the gate-source voltage of the second transistor 1422 decreases, the drain-source current of the second transistor 1422 decreases, and the current flowing out of the high voltage switch circuit 142 decreases. When the current flowing out of the high voltage switch circuit 142 decreases, the drain-source current of the fifth enhancement NMOS 1521 decreases, so that the current divided by the sixth enhancement NMOS 1522 from the first resistor 1423 in the high voltage switch circuit 142 decreases, the current flowing through the second resistor 1424 increases, the gate-source voltage of the second transistor 1422 increases, the drain-source current of the second transistor 1422 increases, and the current flowing out of the high voltage switch circuit 142 increases. The current flowing from the high voltage switching circuit 142 is kept constant by the above adjustment process.

Optionally, the current monitoring unit 154 includes a fourth resistor 1541 and a second enhancement-mode PMOS transistor 1542, wherein a first end of the fourth resistor 1541 is connected to a gate of the second enhancement-mode PMOS transistor 1542, and a second end of the fourth resistor 1541 is connected to a source of the second transistor 1422, a source of the first enhancement-mode PMOS transistor 1533, and an anode of the second diode 1531; the gate of the second enhancement-mode PMOS transistor 1542 is connected to the first end of the fourth resistor 1541, the source of the second enhancement-mode PMOS transistor 1542 is connected to the second end of the fourth resistor 1541, the source of the second transistor 1422, the drain of the first enhancement-mode PMOS transistor 1533, and the anode of the second diode 1531, and the source of the second enhancement-mode PMOS transistor 1542 is connected to the drain of the fifth enhancement-mode NMOS transistor 1521.

Specifically, referring to fig. 2, the fourth resistor 1541 monitors the value of the supply current, and sets a small value of the supply current with the second enhancement PMOS transistor 1542, where the small value of the supply current is the sum of the leakage currents of the fourth resistor 1541 and the second enhancement PMOS transistor 1542, and the current of the fourth resistor 1541 is:

I_1541＝Vth_1542/R_1541

the leakage current of the second enhancement PMOS transistor 1542 is:

Id_1542＝β(Vgs_1542-Vth_1542)²

where β is a factor related to the size of the second enhancement type PMOS transistor 1542, Vth _1542 is the threshold voltage of the second enhancement type PMOS transistor 1542, and R _1541 is the resistance of the fourth resistor 1541;

the small current value I _ S of the supply current is

I_S＝I_1541

After the high voltage switch circuit 142 is turned on, current first flows through the fourth resistor 1541 and the power supply terminal of the first diode 1513 to supply power. When the current flowing through the fourth resistor 1541 is that the voltage at both ends of the fourth resistor 1541 is higher than the threshold of the second enhancement type PMOS transistor 1542, the second enhancement type PMOS transistor 1542 is turned on, the current flowing through the fourth resistor 1541 is shunted by the second enhancement type PMOS transistor 1542, and the current flowing through the fourth resistor 1541 is the ratio of the threshold voltage of the second enhancement type PMOS transistor 1542 to the resistance of the fourth resistor 1541. The threshold of the second enhancement PMOS transistor 1542 is fixed, and the current flowing through the fourth resistor 1541 is kept constant. The magnitude of the current can be adjusted by adjusting the resistance of the fourth resistor 1541, the current value is set to be a small current, and when the power is just powered on or the power supply end is short-circuited, the voltage value of the power supply end is lower than the large current set threshold, and the power needs to be supplied by the small current, so as to prevent the high-voltage switch circuit 10 from being burned due to excessive power consumption.

Optionally, the constant current setting unit 153 includes a second diode 1531, a third diode 1532, a first enhancement type PMOS transistor 1533, and a third resistor 1534, wherein an anode of the second diode 1531 is connected to a source of the first enhancement type PMOS transistor 1533 and a source of the second transistor 1422, and a cathode of the second diode 1531 is connected to an anode of the third diode 1532; the cathode of the third diode 1532 is connected to the gate of the first enhancement PMOS transistor 1533 and the drain of the third enhancement NMOS transistor 1511, and the anode of the third diode 1532 is connected to the cathode of the second diode 1531; the drain of the first enhancement PMOS transistor 1533 is connected to the first end of the third resistor 1534, the gate of the first enhancement PMOS transistor 1533 is connected to the cathode of the third diode 1532, and the source of the first enhancement PMOS transistor 1533 is connected to the anode of the second diode 1531; and a first end of the third resistor 1534 is connected to the drain of the first enhancement PMOS transistor 1533, and a second end of the third resistor 1534 is connected to the gate of the third enhancement NMOS transistor 1511, the anode of the first diode 1513, and the current monitoring unit 154.

Specifically, referring to fig. 2, when the voltage monitoring circuit 151 monitors that the voltage at the power supply terminal is higher than the large current threshold voltage, the comparison circuit of the voltage monitoring circuit 151, i.e., the fourth enhancement type NMOS transistor 1512 is turned on, the first enhancement type PMOS transistor 1533 is turned on, and the current flowing out of the second transistor 1422 flows into the power supply terminal of the chip through the first enhancement type PMOS transistor 1533, the third resistor 1534 and the first diode 1513. The gate-source voltage of first enhancement-mode PMOS transistor 1533 is clamped at two PN junction drops by second diode 1531 and third diode 1532 in series, and first enhancement-mode PMOS transistor 1533 operates in the on-off state with currents flowing through 1533 and 1534 as:

I_1533＝I_1544＝V_1541/R_1534

where V _1541 is the voltage across the resistor 1541, and R _1534 is the resistance of the resistor 1534.

In the on-off state, the source-drain voltage of the first enhancement PMOS transistor 1533 is very small and can be basically ignored, and the current is the current when the voltage of the power supply terminal is higher than the large current threshold value, that is, I _ L is I _ 1533; the third resistor 1534 is connected in series to the drain of the first enhancement PMOS transistor 1533 for adjusting the large charging current I _ L of the capacitor CA connected to VDD.

Further according to a second aspect of the present application, there is provided a high voltage starting circuit 10, referring to fig. 2, the high voltage starting circuit 10, for providing current to a chip 220 in a switching power supply when the switching power supply is started, comprising a current input terminal 110 and a current output terminal 120, wherein the current input terminal 110 is configured to receive high voltage current, and the current output terminal 120 is configured to provide output current to the chip 220, further comprising: a control signal input 130 configured to receive a control signal; the switch circuit module 140 is disposed on a current path between the current input terminal 110 and the current output terminal 120, connected to the control signal input terminal 130, and configured to disconnect the current path from the current input terminal 110 to the current output terminal 120 according to the received control signal.

Specifically, the high voltage start-up circuit 10 includes a current input 110 and a current output 120, wherein the current input 110 is configured to receive the high voltage current from the rectifier 210. The current output 120 is configured to provide an output current to the chip 220. And the high voltage start-up circuit 10 further comprises: the control signal input terminal 130 is used for sending a control signal from the chip 220 and sending the control signal to the switch circuit module 140 through the control signal input terminal 130.

The high voltage start-up circuit 10 further comprises a switch circuit module 140, disposed in a current path between the current input terminal 110 and the current output terminal 120, and connected to the control signal input terminal 130, and configured to disconnect the current path from the current input terminal 110 to the current output terminal 120 according to the received control signal. Therefore, under the condition that the chip in the high-voltage starting circuit is charged, the effect of timely disconnecting the circuit is achieved, and unnecessary loss is avoided. And then the technical problem that the high-voltage starting circuit in the prior art uses large resistors to greatly waste power consumption is solved.

Optionally, the switch control circuit 141 includes a first enhancement NMOS transistor 1411 and a second enhancement NMOS transistor 1412, wherein a drain of the first enhancement NMOS transistor 1411 is connected to a first terminal of the first resistor 1423, a first terminal of the second resistor 1424, and a gate of the second transistor 1422, a source of the first enhancement NMOS transistor 1411 is connected to ground, and a gate of the first enhancement NMOS transistor 1411 is connected to the chip; and the drain of the second enhancement mode NMOS transistor 1412 is connected to the second terminal of the second resistor 1424, the gate of the first transistor 1421, and the source of the second transistor 1422, the source of the second enhancement mode NMOS transistor 1412 is connected to ground, and the gate of the second enhancement mode NMOS transistor 1412 is connected to the chip 220.

The function of the high-voltage start-up circuit 10 according to the second aspect of the present embodiment is the same as that of the high-voltage start-up circuit 10 according to the first aspect of the present embodiment, and therefore, the detailed description thereof is omitted.

Further according to a third aspect of the present application, there is provided a high voltage starting circuit 10, referring to fig. 2, the high voltage starting circuit 10, for providing current to a chip 220 in a switching power supply when the switching power supply is started, comprising a current input terminal 110 and a current output terminal 120, wherein the current input terminal 110 is configured to receive high voltage current, and the current output terminal 120 is configured to provide output current to the chip, further comprising: and a current setting circuit 150, disposed in a current path between the current input terminal 110 and the current output terminal 120, for receiving an input current from the current input terminal 110 and providing an output current to the current output terminal 120 according to a voltage of the current output terminal 120.

Specifically, the high voltage start-up circuit 10 includes a current setting circuit 150 connected to the switching circuit module 140 and the current output terminal 120, and configured to receive an input current from the switching circuit module 140. And is connected with the chip 220 through the current output terminal 120, thereby monitoring the voltage of the current output terminal 120 in real time, and comparing the monitored voltage of the current output terminal 120 with a preset large current threshold value, and setting whether the supply current is a preset large current value or a small current value according to the comparison result. And when the high voltage starting circuit 10 is short-circuited, a small current value is set by the current setting circuit 150, thereby avoiding burning the high voltage starting circuit. And then solved the current high-voltage starting circuit that exists among the prior art and did not have short-circuit protection measure, the technical problem that is burnt easily when the short circuit of high-voltage starting circuit.

Therefore, according to the embodiment of the present application, the power switch circuit 20 and the high voltage starting circuit 10 are provided by disposing the high voltage starting circuit 10 between the rectifier 210 and the chip 220. Wherein the high voltage starting circuit 10 controls the on/off and the magnitude of the starting current by connecting with the rectifier 210.

And the high voltage start-up circuit 10 includes a current input 110 and a current output 120, wherein the current input 110 is configured to receive the high voltage current from the rectifier 210. The current output 120 is configured to provide an output current to the chip. And the high voltage start-up circuit 10 further comprises: the control signal input terminal 130 is used for sending a control signal from the chip 220 and sending the control signal to the switch circuit module 140 through the control signal input terminal 130.

The high voltage start-up circuit 10 further comprises a switch circuit module 140, disposed in a current path between the current input terminal 110 and the current output terminal 120, and connected to the control signal input terminal 130, and configured to disconnect the current path from the current input terminal 110 to the current output terminal 120 according to the received control signal. Therefore, under the condition that the chip in the high-voltage starting circuit is charged, the effect of timely disconnecting the circuit is achieved, and unnecessary loss is avoided.

The high voltage start-up circuit 10 further comprises a current setting circuit 150 connected to the switching circuit module 140 and the current output terminal 120, and configured to receive an input current from the switching circuit module 140. And is connected with the chip 220 through the current output terminal 120, thereby monitoring the voltage of the current output terminal 120 in real time, and comparing the monitored voltage of the current output terminal 120 with a preset large current threshold value, and setting whether the supply current is a preset large current value or a small current value according to the comparison result. And when the high voltage starting circuit 10 is short-circuited, a small current value is set by the current setting circuit 150, thereby avoiding burning the high voltage starting circuit.

In addition, fig. 4 shows a waveform diagram of the high voltage start-up circuit 10, and referring to fig. 4, I _1541 is a current flowing through the fourth resistor 1541 to provide a small charging current I _ S for the capacitor CA connected to VDD. I _1533 is the source-drain current flowing through the first enhancement PMOS tube 1533, providing a large charging current I _ L for the capacitor CA connected to VDD. I _1513 is a current flowing through the first diode 1513, and is a sum of the current I _ S and the current I _ L. Vth _ IL is a large current threshold voltage for charging the capacitor CA connected to VDD. The specific working process is as follows: after the power supply is powered on, the rectifier bridge starts to charge the capacitor CP, the second transistor 1422 is turned on, the capacitor CA connected to the VDD is started to be charged through the fourth resistor 1541 and the first diode 1513, as the voltage on the capacitor CP increases, the current flowing through the fourth resistor 1541 and the first diode 1513 gradually increases, when the current flowing through the fourth resistor 1541 makes the voltage across the fourth resistor 1541 higher than the threshold of the second enhancement type PMOS 1542, the first enhancement type PMOS 1533 is turned on, the current flowing through the fourth resistor 1541 is limited to a small current I _ S, the current magnitude is I _1541 ═ Vth _1542/R _1541, Vth _1542 is the threshold of the second enhancement type PMOS 1542, and R _1 is the resistance of the fourth resistor 1. If VDD is short-circuited to the ground, the current flowing through the high-voltage starting circuit is small current I _ S, so that the high-voltage starting circuit cannot be burnt, and the protection effect is achieved; if VDD is not short-circuited to ground, VDD gradually increases under the charging of I _ S current, when VDD increases to a large current threshold Vth _ IL, the fourth enhancement NMOS transistor 1512 is turned on, and the first enhancement PMOS transistor 1533 is turned on, the current flowing through the first enhancement PMOS transistor 1533 is I _ L — V _1541/R _1534, V _1541 is the voltage across the fourth resistor 1541, R _1534 is the resistance of the third resistor 1534, the voltage across the fourth resistor 1541 is the same as the threshold Vth _1542 of the second enhancement PMOS transistor 1542, and is a fixed value, therefore, the magnitude of I _ L is set by the third resistor 1534; after the first enhancement PMOS transistor 1533 is turned on, the current flowing through the first diode 1513 becomes (I _ S + I _ L), and the capacitor CA connected to VDD will be charged at this current until the high voltage start-up circuit is turned off after the chip is started.

The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In the description of the present disclosure, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are presented only for the convenience of describing and simplifying the disclosure, and in the absence of a contrary indication, these directional terms are not intended to indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be taken as limiting the scope of the disclosure; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

The above description is only for the preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A high voltage start-up circuit (10) for supplying a current to a chip (220) in a switching power supply when the switching power supply is started up, comprising a current input terminal (110) and a current output terminal (120), wherein the current input terminal (110) is configured to receive a high voltage current, and the current output terminal (120) is configured to supply an output current to the chip (220), the high voltage start-up circuit further comprising:

a control signal input (130) configured to receive a control signal;

a switching circuit module (140) arranged in a current path between the current input terminal (110) and the current output terminal (120), connected to the control signal input terminal (130), and configured to break the current path from the current input terminal (110) to the current output terminal (120) according to the received control signal.

2. The high voltage startup circuit (10) of claim 1, wherein the switching circuit module (140) comprises:

a switch control circuit (141), the switch control circuit (141) being connected to the control signal input (130) for generating a switching signal in accordance with a control signal received from the control signal input (130); and

a high voltage switch circuit (142) disposed on a current path from the current input terminal (110) to the current output terminal (120) and connected to the switch control circuit (141), configured to break the current path from the current input terminal (110) to the current output terminal (120) according to a switch signal received from the switch control circuit (141).

3. The high voltage startup circuit (10) of claim 2, further comprising a current setting circuit (150) coupled to the switching circuit module (140) and the current output (120), configured to receive an input current from the switching circuit module (140) and provide the output current to the current output (120) based on a voltage at the current output (120).

4. The high voltage startup circuit (10) of claim 3, wherein the high voltage switching circuit (142) comprises: a first transistor (1421), a second transistor (1422), a first resistor (1423), and a second resistor (1424), wherein

A drain of the first transistor (1421) is connected to the current input terminal (110) and a drain of the second transistor (1422), a source of the first transistor (1421) is connected to a source of the second transistor (1422) through the first resistor (1423) and the second resistor (1424), and a gate of the first transistor (1421) is connected to a first terminal of the first resistor (1423), a source of the second transistor (1422), and the switch control circuit (141);

the drain of the second transistor (1422) is connected to the current input terminal (110), the gate of the second transistor (1422) is connected to the first terminal of the first resistor (1423), the first terminal of the second resistor (1424) and the switch control circuit (141), and the source of the second transistor (1422) is connected to the second terminal of the second resistor (1424) and the current setting circuit (150);

a first terminal of the first resistor (1423) is connected to the gate of the second transistor (1422), a first terminal of the second resistor (1424), and the switch control circuit (141), and a second terminal of the first resistor (1423) is connected to the source of the first transistor (1421); and

a first terminal of the second resistor (1424) is connected to the first terminal of the first resistor (1423), the gate of the second transistor (1422), and the switch control circuit (141), and a second terminal of the second resistor (1424) is connected to the current setting circuit (150).

5. The high voltage startup circuit (10) of claim 4 wherein the switch control circuit (141) comprises a first enhancement mode NMOS transistor (1411) and a second enhancement mode NMOS transistor (1412), wherein

The drain electrode of the first enhancement mode NMOS tube (1411) is connected with the first end of the first resistor (1423), the first end of the second resistor (1424) and the gate electrode of the second transistor (1422), the source electrode of the first enhancement mode NMOS tube (1411) is connected with the ground, and the gate electrode of the first enhancement mode NMOS tube (1411) is connected with the chip (220); and

the drain of the second enhancement mode NMOS transistor (1412) is connected with the second end of the second resistor (1424), the gate of the first transistor (1421) and the source of the second transistor (1422), the source of the second enhancement mode NMOS transistor (1412) is connected with ground, and the gate of the second enhancement mode NMOS transistor (1412) is connected with the chip (220).

6. The high voltage start-up circuit (10) of claim 5, wherein the current setting circuit (150) comprises a voltage monitoring unit (151), a current negative feedback unit (152), a constant current setting unit (153), and a current monitoring unit (154), wherein

The voltage monitoring unit (151) is connected with the current output end (120) and the constant current setting unit (153), and the voltage monitoring unit (151) is used for monitoring the output voltage of the current output end (120) and sending the output voltage to the constant current setting unit (153);

the current negative feedback unit (152) is connected with the current monitoring unit (154), and the current negative feedback unit (152) is used for receiving the input current monitored by the current monitoring unit (154) and adjusting the current of the current setting circuit (150) according to the input current;

the constant current setting unit (153) is connected with the voltage monitoring unit (151), and the constant current setting unit (153) is used for setting the input current according to the input voltage sent by the voltage monitoring unit (151); and

the current monitoring unit (154) is connected with the current negative feedback unit (152) and the current output end (120), and the current monitoring unit (154) is used for monitoring the input current of the chip (220) and sending the input current to the current negative feedback unit (152).

7. The high voltage startup circuit (10) of claim 6, wherein the voltage monitoring unit (151) comprises a third enhancement mode NMOS transistor (1511), a fourth enhancement mode NMOS transistor (1512), and a first diode (1513), wherein

The drain of the third enhancement type NMOS tube (1511) is connected with the constant current setting unit (153), the gate of the third enhancement type NMOS tube (1511) is connected with the current monitoring unit (154), the current negative feedback unit (152) and the anode of the first diode (1513), and the source of the third enhancement type NMOS tube (1511) is connected with the drain of the fourth enhancement type NMOS tube (1512);

the drain electrode of the fourth enhancement mode NMOS tube (1512) is connected with the grid electrode of the fourth enhancement mode NMOS tube (1512) and the source electrode of the third enhancement mode NMOS tube (1511), and the source electrode of the fourth enhancement mode NMOS tube (1512) is connected with the ground; and

the cathode of the first diode (1513) is connected with the current output end (120), and the anode of the first diode (1513) is connected with the drain of the third enhancement type NMOS tube (1511).

8. The high voltage startup circuit (10) of claim 7,

the current negative feedback unit (152) comprises a fifth enhancement mode NMOS tube (1521) and a sixth enhancement mode NMOS tube (1522), wherein the drain electrode of the fifth enhancement mode NMOS tube (1521) is connected with the grid electrode of the fifth enhancement mode NMOS tube (1521), the grid electrode of the sixth enhancement mode NMOS tube (1522), the current monitoring unit (154), and the source electrode of the fifth enhancement mode NMOS tube (1521) is connected with the ground; and the grid electrode of the sixth enhancement type NMOS tube (1522) is connected with the grid electrode of the fifth enhancement type NMOS tube (1521), the drain electrode of the sixth enhancement type NMOS tube (1522) is connected with the grid electrode of the second transistor (1422), the first end of the first resistor (1423), the first end of the second resistor (1424) and the source electrode of the first enhancement type NMOS tube (1411), and the source electrode of the sixth enhancement type NMOS tube (1522) is connected with the ground, and/or

The constant current setting unit (153) comprises a second diode (1531), a third diode (1532), a first enhancement type PMOS tube (1533) and a third resistor (1534), wherein the anode of the second diode (1531) is connected with the source of the first enhancement type PMOS tube (1533) and the source of the second transistor (1422), and the cathode of the second diode (1531) is connected with the anode of the third diode (1532); a cathode of the third diode (1532) is connected to the gate of the first enhancement-mode PMOS transistor (1533) and the drain of the third enhancement-mode NMOS transistor (1511), and an anode of the third diode (1532) is connected to the cathode of the second diode (1531); the drain of the first enhancement-mode PMOS tube (1533) is connected to the first end of the third resistor (1534), the gate of the first enhancement-mode PMOS tube (1533) is connected to the cathode of the third diode (1532), and the source of the first enhancement-mode PMOS tube (1533) is connected to the anode of the second diode (1531); and a first terminal of the third resistor (1534) is connected to the drain of the first enhancement PMOS transistor (1533) and a second terminal of the third resistor (1534) is connected to the gate of the third enhancement NMOS transistor (1511), the anode of the first diode (1513) and the current monitoring unit (154), and/or

The current monitoring unit (154) comprises a fourth resistor (1541) and a second enhancement type PMOS tube (1542), wherein a first end of the fourth resistor (1541) is connected with a gate of the second enhancement type PMOS tube (1542), and a second end of the fourth resistor (1541) is connected with a source of the second transistor (1422), a source of the first enhancement type PMOS tube (1533), and an anode of the second diode (1531); and the gate of the second enhancement mode PMOS transistor (1542) is connected to the first end of the fourth resistor (1541), the source of the second enhancement mode PMOS transistor (1542) is connected to the second end of the fourth resistor (1541), the source of the second transistor (1422), the drain of the first enhancement mode PMOS transistor (1533), and the anode of the second diode (1531), and the source of the second enhancement mode PMOS transistor (1542) is connected to the drain of the fifth enhancement mode NMOS transistor (1521).

9. A high voltage start-up circuit (10) for supplying a current to a chip (220) in a switching power supply when the switching power supply is started up, comprising a current input terminal (110) and a current output terminal (120), wherein the current input terminal (110) is configured to receive a high voltage current, and the current output terminal (120) is configured to supply an output current to the chip (220), the high voltage start-up circuit further comprising:

a current setting circuit (150) arranged in a current path between the current input terminal (110) and the current output terminal (120) for receiving an input current from the current input terminal (110) and providing the output current to the current output terminal (120) according to a voltage of the current output terminal (120).

10. A switching power supply circuit (20) comprising a rectifier (210), a chip (220), and a high voltage start-up circuit (10) disposed between the rectifier (210) and the chip (220), wherein the high voltage start-up circuit (10) comprises a current input (110) and a current output (120), wherein the current input (110) is configured to receive a high voltage current, and the current output (120) is configured to provide an output current to the chip (220), further comprising:

a control signal input (130) configured to receive a control signal;