CN219394688U - Starting circuit of control chip and switching power supply - Google Patents

Abstract

The utility model discloses a starting circuit of a control chip, which relates to the field of power supplies, wherein a control module controls a starting switch to be conducted when the power end of the control chip does not meet starting conditions, and a switching power supply charges a starting capacitor through a starting resistor so as to start the control chip; when the power end of the control chip meets the starting condition, the control starting switch is turned off, so that the starting resistor is not connected into the switching power supply; the circuit of the switch power supply is connected with the starting resistor or not to avoid excessive loss, so that a large amount of loss generated by the starting resistor can be avoided under the condition of meeting the requirement of a low-voltage quick starting control chip, particularly, a large amount of loss under the condition of high-voltage input, the loss of the whole switch power supply in the working process is reduced, the requirement of thermal design is met, the risks of thermal stress and the like are avoided, and the service life of the whole switch power supply is further prolonged. The utility model also discloses a switching power supply which has the same beneficial effects as the starting circuit of the control chip.

Description

Starting circuit of control chip and switching power supply

Technical Field

The utility model relates to the field of power supplies, in particular to a starting circuit of a control chip. The utility model also relates to a switching power supply.

Background

Along with the continuous development of power electronic technology, various power supplies are rapidly developed, wherein the switching power supply has the advantages of small volume, light weight, high conversion efficiency, stable and reliable performance and the like, and is widely applied to products such as industrial control, new energy, consumer electronics and the like, but different application scenes of various industries bring higher requirements to the reliability of the switching power supply, and the switching power supply can normally work under various complex working conditions.

In the field of photovoltaic inverter applications, the auxiliary power supply generally uses a switching power supply, in particular a flyback switching power supply. The output voltage of the photovoltaic module can change along with the change of illumination intensity, taking the photovoltaic module commonly used in the market at present as an example, the voltage output range of the photovoltaic module is usually 140V-1100V, and the auxiliary power supply of the photovoltaic inverter takes power from a bus, so that the switching power supply serving as the auxiliary power supply also needs to meet the requirement that the input voltage can normally work when 140V-1100V, and the defects that the auxiliary power supply is slow to start under low-voltage input and has large loss under high-voltage input can occur.

At present, most of auxiliary power supplies of photovoltaic inverters cannot be started quickly by low-voltage input and have low high-voltage input loss, if the starting resistor of the auxiliary power supply of the inverter is designed by the working condition of low-voltage input, the starting resistor with a smaller resistance value is selected, the starting current of a control chip can be better met, the charging time of a capacitor connected with the power end of the control chip is short, and therefore, although the low-voltage quick start-up can be met, the loss of the starting resistor can be very large due to the rising of the input voltage when the high-voltage input is carried out, if the starting resistor with a larger resistance value is designed on the premise of meeting the high-voltage loss, the starting time of the control chip can be very long when the low-voltage input is carried out, and even the control chip can not be started normally in the outdoor low-temperature weather.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a switching power supply provided in the prior art; the resistors R1, R2 and R3 in fig. 1 together constitute a starting resistor. When the input power supply exists, the current flowing through the starting resistor meets the starting current of the control chip, and after the voltage at the two ends of the starting capacitor C1 corresponding to the power end VCC of the control chip is higher than the opening threshold voltage of the control chip, namely, the starting condition of the control chip is met, the control chip is started normally, and the switching power supply works normally. In order to meet the low-voltage starting design, in practical application, the resistance value of the selected starting resistor is generally not very large, so that very large loss is generated on the starting resistor in the subsequent high-voltage input process, and even the loss during high-voltage input can reach 50 times of the low-voltage input loss under severe conditions.

Disclosure of Invention

The utility model aims to provide a starting circuit of a control chip and a switching power supply, wherein a starting resistor is connected with a circuit of the switching power supply in the starting process of the control chip, and is not connected with the circuit of the switching power supply in the normal working process of the control chip, so that excessive loss is avoided.

In order to solve the technical problems, the utility model provides a starting circuit of a control chip, which is applied to a switching power supply and comprises a starting switch, a starting resistor and a control module; the first end of the starting resistor is connected with the input power supply of the switching power supply, the second end of the starting resistor is connected with the first end of the starting switch, the second end of the starting switch is respectively connected with the power supply end of the control chip and the first end of the starting capacitor of the switching power supply, the input end of the control module is respectively connected with the power supply end of the control chip and the first end of the starting capacitor of the switching power supply, and the output end of the control module is connected with the control end of the starting switch;

The starting switch is used for being conducted based on the control of the control module when the power end of the control chip does not meet the starting condition, so that the power end of the control chip reaches the starting condition; and when the power end of the control chip meets the starting condition, the control is turned off based on the control of the control module.

Preferably, the control module comprises a voltage division module and a switching module; the first input end of the voltage dividing module is connected with a power supply, the output end of the voltage dividing module is connected with the control end of the starting switch and the output end of the switching module respectively, the second input end of the voltage dividing module is grounded, and the input end of the switching module is connected with the power supply end of the control chip and the first end of the starting capacitor of the switching power supply respectively;

the switching module is used for controlling the voltage of the output end of the voltage dividing module to be a first preset voltage when the power end of the control chip does not meet the starting condition so as to control the starting switch to be turned on; when the power end of the control chip meets the starting condition, the voltage of the output end of the voltage dividing module is controlled to be a second preset voltage so as to control the starting switch to be turned off.

Preferably, the control module further includes a first capacitor, a first end of the first capacitor is respectively connected with the output end of the voltage dividing module, a control end of the starting switch is connected with the output end of the switching module, and a second end of the first capacitor is grounded.

Preferably, the voltage dividing module comprises a first stable state resistor and a second stable state resistor; the first end of the first steady-state resistor is connected with a power supply, the second end of the first steady-state resistor is respectively connected with the first end of the second steady-state resistor, the first end of the first capacitor, the control end of the starting switch is connected with the output end of the switching module, and the second end of the second steady-state resistor is grounded.

Preferably, the control module further comprises a voltage stabilizing module; the negative electrode of the voltage stabilizing module is respectively connected with the second end of the first stable resistor, the first end of the second stable resistor, the first end of the first capacitor, the control end of the starting switch and the output end of the switching module are connected, and the positive electrode is grounded.

Preferably, the switching module comprises a switching switch, a switching resistor and a second capacitor; the first end of the second capacitor is respectively connected with the first end of the switching resistor, the control end of the switching switch, the power end of the control chip is connected with the first end of the starting capacitor of the switching power supply, the second end of the control chip is grounded, the second end of the switching resistor is grounded, the first end of the switching switch is grounded, and the second end of the switching switch is connected with the output end of the voltage dividing module;

The switching switch is used for being turned off when the power end of the control chip does not meet the starting condition so as to control the voltage of the output end of the voltage dividing module to be a first preset voltage, so that the starting switch is turned on; and when the power end of the control chip meets a starting condition, the control chip is conducted to control the voltage of the output end of the voltage dividing module to be a second preset voltage so as to enable the starting switch to be turned off.

Preferably, the switching module further comprises a first resistor; the first end of the first resistor is connected with the output end of the voltage dividing module, and the second end of the first resistor is connected with the second end of the change-over switch.

Preferably, the switching module further comprises a second resistor; the first end of the second resistor is respectively connected with the power end of the control chip and the first end of the starting capacitor of the switching power supply, the second end of the second resistor is respectively connected with the first end of the second capacitor, and the first end of the switching resistor is connected with the control end of the switching switch.

Preferably, the switching module further comprises a unidirectional conduction module, the positive electrode of the unidirectional conduction module is respectively connected with the power end of the control chip and the first end of the starting capacitor of the switching power supply, and the negative electrode of the unidirectional conduction module is connected with the first end of the second resistor.

In order to solve the technical problems, the utility model also provides a switching power supply which comprises a starting capacitor, a transformer and a starting circuit of the control chip; the starting circuit of the control chip is respectively connected with the input power supply of the switching power supply, the transformer, the first end of the starting capacitor is connected with the power supply end of the control chip, and the second end of the starting capacitor is grounded.

The utility model provides a starting circuit of a control chip, which is applied to a switching power supply, and comprises a starting switch, a starting resistor and a control module; the control module controls the starting switch to be conducted when the power end of the control chip does not meet the starting condition, the input power of the switching power supply charges the starting capacitor through the starting resistor and the starting switch, so that the power end of the control chip reaches the starting condition, and the control chip is started and works normally; when the power end of the control chip meets the starting condition, the control starting switch is turned off, and the starting resistor is not connected into the switching power supply, so that the loss caused by the starting resistor is avoided in the switching power supply in the normal working process of the control chip; the starting resistor is connected to the circuit of the switching power supply in the starting process of the control chip, and is not connected to the circuit of the switching power supply in the normal working process of the control chip, so that excessive loss is avoided, the mode can avoid the loss caused by always connecting the starting resistor to the switching power supply in the normal working process of the control chip under the condition of meeting the requirement of low-voltage quick starting of the control chip, the defects of low starting speed, high-voltage working loss and the like of the conventional switching power supply are effectively overcome, particularly, a large amount of loss under the condition of high-voltage input is avoided, the loss of the working process of the whole switching power supply is reduced, the requirement of thermal design is met, the risks of thermal stress and the like are avoided, and the service life of the whole switching power supply is further prolonged.

The utility model also provides a switching power supply, which has the same beneficial effects as the starting circuit of the control chip.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required in the prior art and the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a switching power supply provided in the prior art;

fig. 2 is a schematic structural diagram of a starting circuit of a control chip according to the present utility model;

fig. 3 is a schematic structural diagram of a switching power supply provided by the utility model;

fig. 4 is a schematic structural diagram of another switching power supply provided by the utility model.

Detailed Description

The utility model provides a starting circuit of a control chip and a switching power supply, wherein a starting resistor is connected with a circuit of the switching power supply in the starting process of the control chip, and is not connected with the circuit of the switching power supply in the normal working process of the control chip, so that excessive loss is avoided.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The starting circuit of the control chip provided by the utility model is mainly applied to a switching power supply, is usually applied to a process of starting the control chip or the controller through the switching power supply, can be also called as a starting circuit of the switching power supply, can be applied to power electronic equipment such as consumer power supplies, frequency converters, inverters and the like, and can be of various types; the controller may be a UCC28C44 series controller, or may be other types or kinds of controllers. Detailed description of the embodiments are described below.

Referring to fig. 2, fig. 2 is a schematic structural diagram of a start circuit of a control chip according to the present utility model;

referring to fig. 3, fig. 3 is a schematic structural diagram of a switching power supply according to the present utility model; in the figure, vin represents an input power of the switching power supply, vout represents a load side output of the switching power supply, and Vcc represents a power supply terminal of the control chip.

In order to solve the above technical problems, the present utility model provides a control chip start circuit 21, which is applied to a switching power supply, and includes a start switch Q1, a start resistor R1 and a control module 1; the first end of the starting resistor R1 is connected with the input power Vin of the switching power supply, the second end of the starting resistor R1 is connected with the first end of the starting switch Q1, the second end of the starting switch Q1 is respectively connected with the power end of the control chip 2 and the first end of the starting capacitor C1 of the switching power supply, the input end of the control module 1 is respectively connected with the power end of the control chip 2 and the first end of the starting capacitor C1 of the switching power supply, and the output end of the control module 1 is connected with the control end of the starting switch Q1;

the start switch Q1 is used for being controlled to be turned on based on the control module 1 when the power end of the control chip 2 does not meet the start condition, so that the power end of the control chip 2 reaches the start condition; the control of the control module 1 is turned off when the power supply end of the control chip 2 meets the starting condition.

Specifically, the control module 1 may determine whether the power supply end of the control chip 2 meets the starting condition of the control chip 2 at this time according to the voltage of the power supply end of the control chip 2 and the first end of the starting capacitor C1 of the switching power supply, if the power supply end of the control chip 2 does not meet the starting condition at this time, the control module 1 will control the starting switch Q1 to be turned on, the starting resistor R1 is connected to the circuit of the switching power supply through the starting switch Q1, the input power Vin of the switching power supply charges the first end of the starting capacitor C1 through the starting resistor R1 and the starting switch Q1, that is, the voltage of the power supply end of the control chip 2 is increased until the power supply end of the control chip 2 reaches the starting condition, which is the starting stage of the control chip 2; if the power end of the control chip 2 meets the starting condition at this time, the charging process of the starting capacitor C1 can be stopped, the control module 1 controls the starting switch Q1 to be turned off, the starting resistor R1 is not connected into the circuit of the switching power supply at this time, and the control chip 2 is started already at this stage and starts to enter a normal working state. As shown in fig. 3, in the normal working process of the control chip 2, the auxiliary winding of the transformer T1 can be directly used as a power supply source, so as to realize the normal working of the control chip 2.

Considering that the starting resistor R1 in the prior art can cause a large amount of loss, particularly when the condition of low-voltage quick starting is met, the starting resistor R1 with smaller resistance value is set, the formula p=u2/R can know that the loss is in direct proportion to the square of voltage, the starting resistor R1 with smaller resistance value can cause very large loss, meanwhile, when the input power Vin of the switching power supply is in the condition of high-voltage input, the starting resistor R1 can cause more loss, the starting resistor R1 is connected with the starting resistor R1 through setting the starting switch Q1, whether the starting resistor R1 is connected with the switching power supply is realized through the on and off of the starting switch Q1, the starting of the control chip 2 is realized through the connected starting resistor R1 in the starting stage of the control chip 2, namely, the starting resistor R1 with smaller resistance value is selected, the starting resistor R1 is not connected with the switching power supply in the normal working stage of the control chip 2, the starting resistor R1 is disconnected from the circuit of the switching power supply, the starting resistor R1 and the loss is not generated in the circuit of the switching power supply is not connected with the switching power supply, and the large loss is avoided due to the fact that the starting loss is generated in the starting power supply is not connected with the switching power supply.

It can be understood that the power end of the control chip 2 is connected to the first end of the start capacitor C1, and the start resistor R1 and the start switch Q1 charge the start capacitor C1, that is, increase the voltage of the first end of the start capacitor C1, and increase the voltage of the power end of the control chip 2, so that the start of the control chip 2 is realized through the charging process of the start capacitor C1.

It should be noted that whether the power supply terminal of the control chip 2 meets the start condition refers to whether the current flowing through the start resistor R1 meets the start current of the control chip 2, and the voltage of the power supply terminal of the control chip 2, that is, the voltage of the two ends of the start capacitor C1, is higher than the turn-on threshold voltage of the control chip 2, and correspondingly, the control module 1 generally determines whether the power supply terminal of the control chip 2 meets the start condition according to the voltage signals of the power supply terminal of the control chip 2 and the first end of the start capacitor C1 of the switching power supply, or may be a current signal or other types of electrical characteristics, which is not limited herein.

Specifically, the specific types and implementation manners of the start switch Q1 and the start resistor R1 are not particularly limited herein, and the start switch Q1 may be a switching device such as a power electronic switch or a relay, and a power electronic switch, such as a MOS (Metal-Oxide-Semiconductor Field-Effect Transistor, metal-Oxide semiconductor field effect transistor), a triode, etc., and there are multiple types of choices, and may be selected according to actual application requirements and application environments; the starting resistor R1 may be a fixed resistor, a variable resistor or other impedance modules may be selected, the specific value of the starting resistor R1 may be selected and adjusted according to the starting requirement speed of the control chip 2 or other factors, and different values may exist for the starting resistor R1 of different types of control chips 2. The specific circuit structure and implementation manner of the control module 1 are not particularly limited herein, and the specific circuit structure or selection type of the control module 1 can be adjusted to achieve lower loss, and the control process of the control end of the start switch Q1 can be achieved in various manners.

According to the control chip, the control module 1 and the starting switch Q1 are added to realize efficient operation in the full voltage range of the switching power supply serving as an auxiliary power supply, the starting resistor R1 is designed according to the low-voltage input working condition, the starting resistor R1 can be quickly started under the low-voltage input working condition, the control chip 2 corresponding to the auxiliary power supply is required to bypass the starting resistor R1 after being started, so that the power consumption of the starting resistor R1 can be obviously reduced, the purposes of quick starting at low voltage and low steady-state working loss are achieved, meanwhile, the design choice of the starting resistor R1 is not limited, PWM main control chips or other control chips 2 of different brands can be compatible, and the material substitution and subsequent updating iteration of the main control chip are also facilitated.

At the starting time of the switching power supply, current is rapidly charged through a starting resistor R1 and a starting switch Q1 to a starting capacitor C1 connected with a power end VCC of a control chip 2, after the voltage reaches the starting threshold voltage of a main control chip, the control chip 2 is started and enters a normal working stage, the whole switching power supply can normally work, a power supply winding of a transformer T1, also called an auxiliary winding, outputs stable direct-current voltage to power the starting capacitor C1 after being rectified by a diode D3, and simultaneously is used for supplying power to the power end VCC of the control chip 2, and meanwhile, the power supply winding can also supply power to the control module 1, when the control module 1 detects that the power is supplied, the starting resistor R1 is disconnected from the starting capacitor C1, and at the moment, the starting resistor R1 is not connected into a circuit of the switching power supply any more, so that the loss of steady-state working is very low, even under a high-voltage input working condition, the loss of the whole system can be reduced, the thermal stress can be reduced, and the stability and the service life of the power supply system can be improved.

The utility model provides a starting circuit 21 of a control chip, which is applied to a switching power supply, and comprises a starting switch Q1, a starting resistor R1 and a control module 1; the control module 1 controls the starting switch Q1 to be conducted when the power end of the control chip 2 does not meet the starting condition, the input power Vin of the switching power supply charges the starting capacitor C1 through the starting resistor R1 and the starting switch Q1, the power end of the control chip 2 is enabled to reach the starting condition, and the control chip 2 is started and works normally; when the power end of the control chip 2 meets the starting condition, the control starting switch Q1 is turned off, and the starting resistor R1 is not connected into the switching power supply, so that the loss caused by the starting resistor R1 does not exist in the switching power supply in the normal working process of the control chip 2; the starting resistor R1 is connected to the circuit of the switching power supply in the starting process of the control chip 2, and is not connected to the circuit of the switching power supply in the normal working process of the control chip 2, so that excessive loss is avoided, the mode can avoid the loss caused by the fact that the starting resistor R1 is always connected to the switching power supply in the normal working process of the control chip 2 under the condition of meeting the requirement of low-voltage quick starting of the control chip 2, the defects of low starting speed, high working loss and the like of the conventional switching power supply are effectively overcome, particularly, a large amount of loss under the condition of high-voltage input is avoided, the loss of the whole switching power supply in the working process is reduced, the requirement of thermal design is met, the risks such as thermal stress are avoided, and the service life of the whole switching power supply is further prolonged.

On the basis of the above-described embodiments,

as a preferred embodiment, the control module 1 comprises a voltage dividing module and a switching module; the first input end of the voltage dividing module is connected with a power supply, the output end of the voltage dividing module is respectively connected with the control end of the starting switch Q1 and the output end of the switching module, the second input end of the voltage dividing module is grounded, and the input end of the switching module is respectively connected with the power supply end of the control chip 2 and the first end of the starting capacitor C1 of the switching power supply;

the switching module is used for controlling the voltage of the output end of the voltage dividing module to be a first preset voltage when the power end of the control chip 2 does not meet the starting condition so as to control the starting switch Q1 to be turned on; when the power end of the control chip 2 meets the starting condition, the voltage of the output end of the control voltage division module is a second preset voltage so as to control the starting switch Q1 to be turned off.

Specifically, the control module 1 includes a voltage dividing module and a switching module, an output end of the voltage dividing module is connected with a control end of the start switch Q1, a stable voltage is output under control of the switching module, and the switching module can adjust the voltage of the output end of the voltage dividing module according to the monitored condition of the power end of the control chip 2, so as to control on and off of the start switch Q1. If the switch Q1 is turned on to select the MOS transistor and is an N-channel MOS transistor, the first preset voltage is higher than the second preset voltage, and the NMOS transistor is turned on at the control end, i.e., when the voltage of the gate is higher, and turned off when the voltage of the gate is lower. Generally, the switching module is connected to the power end of the control chip 2 through the auxiliary winding of the transformer T1, so as to monitor the condition of the power end of the control chip 2, and meanwhile, the switching module and the control chip 2 share the auxiliary winding as a power supply source, which is more beneficial to realizing the accurate control process of the switching module.

Specific circuit structures, implementation modes and the like of the voltage dividing module and the switching module are not particularly limited, and the voltage dividing module can be realized by a simple circuit with series resistors or by means of devices such as a voltage stabilizing module; the voltage control of the output end of the voltage dividing module by the switching module is also realized in various ways, and the change of the circuit structure and the like can be realized by the on-off of the control circuit.

The control module 1 is realized through the voltage dividing module and the switching module, the voltage dividing module outputs stable voltage under the control of the switching module, the switching module realizes the control of the starting switch Q1 by adjusting the voltage output by the voltage dividing module, the function of the control module 1 is effectively realized, the control of the starting switch Q1 is realized by directly controlling the voltage of the control end of the starting switch Q1, the control mode is simple and effective, the control mode is easy to realize, the stable voltage output by the voltage dividing module can improve the accuracy and the stability of the whole control process, and the accurate realization of the whole starting circuit is further ensured.

As a preferred embodiment, the control module 1 further includes a first capacitor C4, where a first end of the first capacitor C4 is connected to the output end of the voltage dividing module, a control end of the start switch Q1 is connected to the output end of the switching module, and a second end is grounded.

Specifically, a first capacitor C4 is additionally arranged in the control module 1, the first capacitor C4 is connected between the output end of the voltage dividing module and the ground in parallel, on one hand, the adjustment of the output voltage of the voltage dividing module by the switching module can be further embodied through the charging and discharging process of the first capacitor C4, and the time sequence setting of the control process can be realized through adjusting the parameters of the capacitor or the internal circuit of the voltage dividing module, on the other hand, the first capacitor C4 connected in parallel can also have the functions of filtering and stabilizing circuits, so that the anti-interference capability of the whole control module 1 can be improved, and the accurate realization of the control module 1 is ensured.

The application of the parameter value and specific type of the first capacitor C4 is not particularly limited, and considering that the application requirement of low-voltage quick start needs to be met, the first capacitor C4 with smaller capacitance value can be selected, so that the voltage of the control end of the start switch Q1 can reach the required value more quickly, the control process is accelerated, and the response speed is ensured.

The first capacitor C4 connected in parallel between the output end of the voltage dividing module and the ground is additionally arranged in the control module 1, so that the control and adjustment process of the voltage of the output end of the voltage dividing module by the switching module is facilitated, meanwhile, the anti-interference capability of a circuit can be improved, the accuracy and the reliability of the whole control module 1 are ensured, and the accurate realization of the whole starting circuit is further ensured.

As a preferred embodiment, the voltage dividing module comprises a first steady-state resistor and a second steady-state resistor R8; the first end of the first steady-state resistor is connected with a power supply, the second end of the first steady-state resistor is respectively connected with the first end of the second steady-state resistor R8, the first end of the first capacitor C4, the control end of the starting switch Q1 is connected with the output end of the switching module, and the second end of the second steady-state resistor R8 is grounded.

Specifically, the voltage dividing module is realized through a first stable resistor and a second stable resistor R8 which are connected in series, the voltage dividing module is realized through simple resistor series connection, and the output of stable voltage is realized through the voltage division of the resistors. In addition, considering the requirement of thermal design, the thermal stress risk is avoided, the first stable state resistor and the second stable state resistor R8 can be realized by adopting series-parallel connection of a plurality of resistors, as in fig. 3, the first stable state resistor is realized by the resistors R2 and R3 which are connected in series, the service life of the circuit can be prolonged, and the conditions of excessive heating and the like are avoided. Specific values, implementation modes and the like of the first stable resistor and the second stable resistor R8 are not particularly limited herein, and the first stable resistor and the second stable resistor can be realized through a single resistor, can also be realized by means of serial-parallel connection of a plurality of resistors, can adopt a fixed resistor, can also adopt an impedance module such as a variable resistor and the like, and can be selected and adjusted according to actual application requirements, actual application environments and the like.

It should be noted that, the power supply of the voltage dividing module may be an input power Vin directly adopting a switching power supply, and at this time, since the control module 1 is also designed to be connected in a circuit of the switching power supply, in order to avoid loss caused by the control module 1, the resistances of the first stable resistor and the second stable resistor R8 may be appropriately selected to be resistances with slightly larger resistances; the power supply source can also adopt other external power sources, and the type and the specific implementation mode of the power supply source of the voltage dividing module are not particularly limited herein, and can be adjusted according to actual application requirements, the specific circuit structure of the switching power supply and the like.

The voltage division module is realized through the first stable resistor and the second stable resistor R8 which are connected in series, the circuit structure is simple, the voltage division module is easy to realize, the functions of the voltage division module are effectively realized, the adopted components are low in cost and easy to realize, the simple realization of the whole control module 1 is facilitated, the cost of the whole starting circuit is reduced, and the wide application of the starting circuit is facilitated.

As a preferred embodiment, the control module 1 further comprises a voltage stabilizing module D1; the negative electrode of the voltage stabilizing module D1 is respectively connected with the second end of the first stable resistor, the first end of the second stable resistor R8, the first end of the first capacitor C4, the control end of the starting switch Q1 and the output end of the switching module, and the positive electrode is grounded.

Considering that the control module 1 is in the control process to the start switch Q1, it is required to ensure that the voltage of the control end of the start switch Q1 is always kept in a stable state, on the basis of the voltage division module, the control module 1 is further provided with a voltage stabilizing module D1, and the voltage stabilizing module D1 is connected between the output end of the voltage division module and the ground, so that the stability of the voltage of the output end of the voltage division module is further improved. The voltage stabilizing module D1 may select a voltage stabilizing device such as a voltage stabilizing diode or a linear voltage stabilizing source, which is not limited herein, and may be selected and adjusted according to actual application requirements and a specific circuit structure of the switching power supply.

Specifically, the voltage stabilizing module D1 connected between the output end of the voltage dividing module and the ground is additionally arranged, the circuit structure is simple and easy to realize, the stability of the voltage of the output end of the voltage dividing module can be further improved, the accurate control of the starting switch Q1 is ensured, the misoperation of the starting switch Q1 caused by the fluctuation of the voltage is further avoided, the stability of the circuit of the whole control module 1 is improved, and the accuracy and the reliability of the whole starting circuit are ensured.

As a preferred embodiment, the switching module comprises a switching switch Q2, a switching resistor R7 and a second capacitor C2; the first end of the second capacitor C2 is respectively connected with the first end of the switching resistor R7, the control end of the switching switch Q2, the power end of the control chip 2 and the first end of the starting capacitor C1 of the switching power supply, the second end of the switching resistor R7 is grounded, the first end of the switching switch Q2 is grounded, and the second end of the switching switch Q2 is connected with the output end of the voltage dividing module;

The change-over switch Q2 is used for being turned off when the power end of the control chip 2 does not meet the starting condition, so as to control the voltage of the output end of the voltage dividing module to be a first preset voltage, and the starting switch Q1 is turned on; when the power end of the control chip 2 meets the starting condition, the control chip is conducted to control the voltage of the output end of the voltage division module to be a second preset voltage so as to turn off the starting switch Q1.

Specifically, the voltage of the output end of the voltage dividing module is adjusted by the switching module through switching on and off of the switching switch Q2; the change-over switch Q2 is turned on and off according to the monitored condition of the power end of the control chip 2, generally, the change-over switch Q2 is connected with the power end of the control chip 2 through the auxiliary winding of the transformer T1 so as to monitor the condition of the power end of the control chip 2, and meanwhile, the switch module and the control chip 2 share the auxiliary winding as a power supply source, which is more beneficial to realizing the accurate control process of the switch module. If the power supply end of the control chip 2 does not meet the starting condition at this time, the power supply requirement of the auxiliary winding of the transformer T1 cannot meet the conduction condition of the change-over switch Q2, the change-over switch Q2 is turned off at this time, the voltage of the output end of the voltage dividing module is a first preset voltage, the starting switch Q1 is turned on under the drive of the first preset voltage, the input power Vin of the switching power supply charges the starting capacitor C1 through the starting resistor R1 and the starting switch Q1, and the voltage of the power supply end of the control chip 2 is improved; if the power supply end of the control chip 2 meets the starting condition, the voltage of the auxiliary winding is enough to supply the control chip 2 to work normally, meanwhile, the conduction condition of the change-over switch Q2 is also achieved, the change-over switch Q2 is conducted, the voltage of the output end of the voltage dividing module is a second preset voltage, the starting switch Q1 is turned off under the action of the second preset voltage, and the starting resistor R1 is disconnected from the circuit of the switching power supply.

It is to be understood that, the specific type and implementation of the switch Q2 are not particularly limited herein, and the switch Q2 may be a switching device such as a power electronic switch or a relay, and the power electronic switch, such as a MOS transistor, a triode, etc., may be selected in various types, and may be selected according to practical application requirements and application environments.

Specifically, the switching resistor R7 can maintain the voltage input into the switching module, that is, the voltage output by the auxiliary winding, at a stable value, so that the switching switch Q2 can be turned on and off based on the input voltage, the malfunction of the switching switch Q2 is avoided, the stability and accuracy of the switching module are ensured, and meanwhile, the switching resistor R7 can also provide a discharge loop for the second capacitor C2; the second capacitor C2 is combined with the switching resistor R7 to form a simple RC filter circuit, so that the anti-interference capability and stability of the whole control module 1 can be improved, and the control module 1 can be accurately realized; on the other hand, the on/off of the switch Q2 may be further reflected by the charge/discharge process of the first capacitor C4, and meanwhile, the time sequence setting of the control process may be achieved by adjusting the parameters of the capacitor or the internal circuit of the voltage division module.

The specific values and implementation modes of the switching resistor R7 and the second capacitor C2 are not particularly limited herein, and the switching resistor R7 may be a fixed resistor or an impedance module such as a variable resistor, and the specific values and implementation modes may be selected and adjusted according to actual application requirements, actual application environments, etc.; in order to improve the response speed, the second capacitor C2 with a smaller capacitance value can be selected, and the second capacitor C2 with other parameter settings can be selected and adjusted according to the actual application requirements, the actual application environment and the like.

Specifically, the voltage regulation process of the switching module to the output end of the voltage dividing module is realized through the on and off of the switching switch Q2, the stable action of the switching switch Q2 is realized through the cooperation between the switching switch Q2 and the switching resistor R7, the function of the switching module is effectively realized, the circuit structure is simple, the implementation is easy, the accurate implementation of the switching module is further ensured through ensuring the accurate and stable action process of the switching switch Q2, the accuracy and the stability of the control module 1 are improved, and the reliability and the stability of the whole starting circuit are ensured.

As a preferred embodiment, the switching module further comprises a first resistor R4; the first end of the first resistor R4 is connected with the output end of the voltage dividing module, and the second end of the first resistor R4 is connected with the second end of the change-over switch Q2.

Considering that the first end of the change-over switch Q2 is directly grounded, in order to avoid the direct grounding of the voltage of the output end of the voltage division module, a first resistor R4 connected between the output end of the voltage division module and the second end of the change-over switch Q2 is added, and when the change-over switch Q2 is turned off, the first resistor R4 is not connected into a circuit; when the change-over switch Q2 is turned on, the first resistor R4 is connected in parallel with the second steady-state resistor R8, so that the voltage of the output end of the voltage dividing module is reduced, meanwhile, the first resistor R4 and the change-over switch Q2 can provide a quick discharging loop for the first capacitor C4, the voltage of the output end of the voltage dividing module, namely the control end of the starting switch Q1, is quickly reduced, the starting switch Q1 is turned off, and the effect of disconnecting the starting resistor R1 is achieved. The specific value, type, implementation mode and the like of the first resistor R4 are not particularly limited herein, and may be a fixed resistor, or may be an impedance module such as a variable resistor, where the specific value, implementation mode and the like may be selected and adjusted according to the actual application requirement, the actual application environment and the like.

Specifically, the first resistor R4 connected between the output end of the voltage dividing module and the second end of the change-over switch Q2 is added, so that the control end of the starting switch Q1 is prevented from being directly grounded, the circuit structure is simple, the implementation is easy, the voltage adjustment process of the control end of the starting switch Q1 is quickened, the response speed of the whole control module 1 is improved, the working efficiency is improved, the time is saved, and the wide application of the whole starting current is facilitated.

As a preferred embodiment, the switching module further comprises a second resistor R5; the first end of the second resistor R5 is respectively connected with the power end of the control chip 2 and the first end of the starting capacitor C1 of the switching power supply, the second end is respectively connected with the first end of the second capacitor C2, and the first end of the switching resistor R7 is connected with the control end of the switching switch Q2.

Considering that the voltages of the control ends of the different types of the change-over switches Q2 need to be adjusted, meanwhile, the voltages of the control ends of the change-over switches Q2 can be different under different working conditions, the second resistor R5 is additionally arranged, the second resistor R5 and the change-over resistor R7 form a voltage dividing circuit, the voltage output to the control ends of the change-over switches Q2 can be kept stable, and meanwhile, the adjustment of the voltages of the control ends of the change-over switches Q2 can be realized by adjusting the resistance values of the change-over resistor R7 and the second resistor R5, so that the whole circuit is more flexible and convenient to adjust. The specific value, implementation and the like of the second resistor R5 are not particularly limited herein, and may be a fixed resistor, or may be an impedance module such as a variable resistor, and the specific value, implementation and the like may be selected and adjusted according to the actual application requirements, the actual application environment and the like.

Specifically, a second resistor R5 connected with the control end of the change-over switch Q2 is added, the voltage stability of the control end of the change-over switch Q2 is improved through a voltage dividing circuit formed by the second resistor R5 and the change-over resistor R7, the accurate action of the change-over switch Q2 is ensured, the misoperation of the change-over switch Q2 is avoided, meanwhile, the voltage output by the voltage dividing circuit can be changed through adjusting the second resistor R5 and the change-over resistor R7, the whole change-over module is more flexible and convenient to adjust, the wide application of the control module 1 is facilitated, and the application range and the application scene of the whole starting circuit are expanded.

As a preferred embodiment, the switching module further includes a unidirectional conduction module D2, where an anode of the unidirectional conduction module D2 is connected to a power supply end of the control chip 2 and a first end of a start capacitor C1 of the switching power supply, and a cathode of the unidirectional conduction module D2 is connected to a first end of the second resistor R5.

The unidirectional conduction module D2 is additionally arranged in consideration of possible current backflow conditions in the switching module, the direction of current input to the switching module is regulated, the conditions of device damage and circuit failure caused by current backflow are avoided, and the accuracy and the safety of the switching module are further ensured. The type and specific implementation of the unidirectional conduction module D2 are not particularly limited herein, and devices such as a diode and unidirectional silicon may be selected for implementation.

Specifically, the unidirectional conduction module D2 is additionally arranged in the switching module, so that the current backflow in the switching module can be avoided, the accuracy and the safety of the switching module are further ensured, the safety of the whole control module 1 is improved, the effective realization of the control module 1 is ensured, the wide application of the control module 1 is facilitated, the application range and the application scene of the whole starting circuit are expanded, and the safety and the reliability of the whole starting circuit are ensured.

As a specific embodiment, please refer to fig. 3, wherein the voltage stabilizing module D1 employs a 12V voltage stabilizing diode, and the resistance of the starting resistor R1 is much smaller than the resistance of R2 and R3 in the first voltage stabilizing resistor. When the switch power supply is electrified, an input voltage Vin is limited by a resistor R2 and a resistor R3 and then generates stable 12V voltage at two ends of a voltage stabilizing module D1, the voltage stabilizing module D is used for controlling a MOS tube Q1 serving as a starting switch to be conducted, the capacity of a capacitor C4 is very small, so that the time for establishing the 12V voltage is very fast, when the starting switch Q1 is conducted, the input voltage charges a starting capacitor C1 connected with a power end VCC of a control chip through the starting resistor R1 and the starting switch Q1, when the voltage at two ends of the starting capacitor C1 reaches the opening threshold voltage of the control chip, the control chip starts to work, then a power supply winding of a transformer T1 outputs stable direct current voltage after being rectified by a rectifier diode D3, and charges the starting capacitor C1 after being limited by a resistor R6, namely, the power end VCC of the control chip is supplied with power, and meanwhile, the power supply winding charges a second capacitor C2 through a second resistor R5 after being rectified by a rectifier diode D2, and when the voltage at two ends of the second capacitor C2 reaches the conducting threshold value of the switching switch Q2, the switching switch Q2 is conducted, and meanwhile the power supply winding is used as a conducting resistor between the switching end and the switching end of the switching transistor S2 is prevented from being discharged; after the switch Q2 is turned on, the first capacitor C4 discharges through a very small first resistor R4 via the switch Q2, so as to ensure that the voltage at two ends of the first capacitor C4 is lower than the turn-on threshold of the start switch Q1, and thus the start switch Q1 is turned off, and the electrical connection between the start resistor R1 and the start capacitor C1 is disconnected.

In the scheme, the value of the starting capacitor R1 can be selected to be smaller, the design that the starting capacitor C1 can be charged rapidly when low voltage is input is met, and the starting speed of the control chip is improved; the resistance values of R2 and R3 can be larger, so that even under the condition of high-voltage input, the current flowing through R2 and R3 is small, the loss is reduced, and in addition, the first capacitor C4 can use 0.1 mu F capacity, so that the starting switch Q1 can be conducted more quickly.

In the method, the starting resistor R1 and the starting switch Q1 with smaller resistance values are used for realizing the rapid charging of the starting capacitor C1, so that the control chip is rapidly started; in a loop of the control module, the resistance values of R2 and R3 serving as a first steady-state resistor are larger, and the loss is smaller after steady-state operation; meanwhile, the control module is connected with the auxiliary winding through the rectifier diode D2, the second resistor R5 and the second capacitor C2, when the switching power supply is started, voltage is applied to the auxiliary winding, the second capacitor C2 is charged after being rectified through the rectifier diode D2, and when the voltage at two ends of the second capacitor C2 reaches the conduction threshold value of the change-over switch Q2, the starting switch is disconnected and is switched into a circuit of the control module, so that the advantages of quick start-up of low-voltage input, low high-voltage input loss and the like can be achieved at the same time, the defect of thermal stress of an auxiliary power supply system is effectively overcome, and the stability and reliability of the system are improved.

Referring to fig. 4, fig. 4 is a schematic structural diagram of another switching power supply provided by the present utility model.

In order to solve the above technical problems, the present utility model further provides a switching power supply, which includes a start capacitor C1, a transformer T1, and a start circuit 21 of the control chip as described above; the starting circuit 21 of the control chip is respectively connected with the input power Vin of the switching power supply, the transformer T1, the first end of the starting capacitor C1 and the power end of the control chip 2, and the second end of the starting capacitor C1 is grounded.

Specifically, the specific type and implementation of the switching power supply are not specifically limited herein, and the switching power supply includes, but is not limited to, a start capacitor C1, a transformer T1, and a start circuit 21 of a control chip as described above, and the specific type and implementation of the start capacitor C1, the transformer T1, and the start circuit 21 of the control chip are not specifically limited herein, and the specific type and the like of the control chip 2 to which the switching power supply is applied are not specifically limited herein, and may be a PWM type control chip 2, or may be other types; the specific connection manner and implementation circuit of the starting circuit 21 of the control chip and the input power Vin of the switching power supply and the transformer T1 are not particularly limited herein, and may be adjusted and selected according to the specific structure of the switching power supply in practical application.

For the description of the switching power supply provided by the present utility model, reference is made to the embodiment of the start circuit 21 of the control chip, and the description of the embodiment is omitted herein.

It should also be noted that in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present utility model is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The starting circuit of the control chip is characterized by being applied to a switching power supply, and comprises a starting switch, a starting resistor and a control module; the first end of the starting resistor is connected with the input power supply of the switching power supply, the second end of the starting resistor is connected with the first end of the starting switch, the second end of the starting switch is respectively connected with the power supply end of the control chip and the first end of the starting capacitor of the switching power supply, the input end of the control module is respectively connected with the power supply end of the control chip and the first end of the starting capacitor of the switching power supply, and the output end of the control module is connected with the control end of the starting switch;

the starting switch is used for being conducted based on the control of the control module when the power end of the control chip does not meet the starting condition, so that the power end of the control chip reaches the starting condition; and when the power end of the control chip meets the starting condition, the control is turned off based on the control of the control module.

2. The start-up circuit of the control chip of claim 1, wherein the control module comprises a voltage division module and a switching module; the first input end of the voltage dividing module is connected with a power supply, the output end of the voltage dividing module is connected with the control end of the starting switch and the output end of the switching module respectively, the second input end of the voltage dividing module is grounded, and the input end of the switching module is connected with the power supply end of the control chip and the first end of the starting capacitor of the switching power supply respectively;

The switching module is used for controlling the voltage of the output end of the voltage dividing module to be a first preset voltage when the power end of the control chip does not meet the starting condition so as to control the starting switch to be turned on; when the power end of the control chip meets the starting condition, the voltage of the output end of the voltage dividing module is controlled to be a second preset voltage so as to control the starting switch to be turned off.

3. The control chip start-up circuit of claim 2, wherein the control module further comprises a first capacitor, a first end of the first capacitor is respectively connected with the output end of the voltage dividing module, a control end of the start switch is connected with the output end of the switching module, and a second end of the first capacitor is grounded.

4. The control chip start-up circuit of claim 3, wherein the voltage divider module includes a first steady state resistor and a second steady state resistor; the first end of the first steady-state resistor is connected with a power supply, the second end of the first steady-state resistor is respectively connected with the first end of the second steady-state resistor, the first end of the first capacitor, the control end of the starting switch is connected with the output end of the switching module, and the second end of the second steady-state resistor is grounded.

5. The control chip start-up circuit of claim 4, wherein the control module further comprises a voltage regulator module; the negative electrode of the voltage stabilizing module is respectively connected with the second end of the first stable resistor, the first end of the second stable resistor, the first end of the first capacitor, the control end of the starting switch and the output end of the switching module are connected, and the positive electrode is grounded.

6. The control chip start-up circuit of claim 2, wherein the switching module comprises a switch, a switching resistor and a second capacitor; the first end of the second capacitor is respectively connected with the first end of the switching resistor, the control end of the switching switch, the power end of the control chip is connected with the first end of the starting capacitor of the switching power supply, the second end of the control chip is grounded, the second end of the switching resistor is grounded, the first end of the switching switch is grounded, and the second end of the switching switch is connected with the output end of the voltage dividing module;

the switching switch is used for being turned off when the power end of the control chip does not meet the starting condition so as to control the voltage of the output end of the voltage dividing module to be a first preset voltage, so that the starting switch is turned on; and when the power end of the control chip meets a starting condition, the control chip is conducted to control the voltage of the output end of the voltage dividing module to be a second preset voltage so as to enable the starting switch to be turned off.

7. The start-up circuit of the control chip of claim 6, wherein the switching module further comprises a first resistor; the first end of the first resistor is connected with the output end of the voltage dividing module, and the second end of the first resistor is connected with the second end of the change-over switch.

8. The control chip start-up circuit of claim 7, wherein the switching module further comprises a second resistor; the first end of the second resistor is respectively connected with the power end of the control chip and the first end of the starting capacitor of the switching power supply, the second end of the second resistor is respectively connected with the first end of the second capacitor, and the first end of the switching resistor is connected with the control end of the switching switch.

9. The control chip start-up circuit of claim 8, wherein the switching module further comprises a unidirectional conduction module, an anode of the unidirectional conduction module is connected to a power supply terminal of the control chip and a first terminal of a start-up capacitor of the switching power supply, respectively, and a cathode of the unidirectional conduction module is connected to a first terminal of the second resistor.

10. A switching power supply comprising a start-up capacitor, a transformer and a start-up circuit of the control chip according to any one of claims 1 to 9; the starting circuit of the control chip is respectively connected with the input power supply of the switching power supply, the transformer, the first end of the starting capacitor is connected with the power supply end of the control chip, and the second end of the starting capacitor is grounded.