TWI397237B - Switch power and electronic device using thereof - Google Patents

Description

Switching power supply and electrical equipment using the same

The present invention relates to an electronic device, and more particularly to a switching power supply and a powered device using the same.

The popularity of various types of electrical equipment such as televisions, computers, and home theaters has greatly enriched our lives and brought great convenience to our lives.

Power supplies for electrical equipment are generally supplied by power stations, transmitted to various regions via high-voltage transmission lines, and converted to standard voltages (220 volts in mainland China) by substations in various regions to thousands of households. . Nowadays, many electrical equipments work under a certain range of DC current. For example, the normal working voltage of a notebook computer is 12.5 volts. Therefore, a switching power supply is usually used to convert the substation output to the standard voltage of the user's home for conversion. The operating voltage within a specified range of electrical equipment.

A switching element is generally provided inside the switching power supply, and the switching element is used to control whether the switching power supply supplies an operating voltage to the outside. When the switching element is turned on, the output current is turned on, and a detecting module is further disposed in the switching power supply, and the detecting module is configured to detect the magnitude of the conducting current. When the detection module detects that the conduction current is too large, the switching element stops outputting the conduction current. If the detection module is short-circuited, it will not detect that the conduction current is too large, and the excessive conduction current will burn out the switching power supply, which will seriously cause a fire.

In view of this, it is necessary to provide a switching power supply having a short circuit protection function.

It is also necessary to provide a powered device with short circuit protection.

A switching power supply, comprising: an input unit for receiving an external voltage, a first rectifying unit for rectifying and filtering an external current, outputting a direct current, a control unit, a conversion unit, a switching unit, a detecting unit, and a protection unit, the control unit The unit is configured to start and output a control signal to the switch unit after receiving the external voltage, the switch unit is turned on by receiving the control signal, and the conversion unit receives the DC current and outputs the DC current to the detection unit when the switch unit is turned on. The detecting unit is configured to receive the DC current to generate a detecting current, and generate a detecting voltage according to the detecting current. When the detecting unit detects that the detecting voltage is too high, the control unit stops outputting the control signal, and the protection unit is connected to the switching unit. And absorbing the DC current when the DC current is too large and the control unit does not detect the detection voltage.

The utility model relates to a power consumption device, comprising a switching power supply and a working module. The switching power supply comprises an input unit for receiving an external voltage, a first rectifying unit for rectifying and filtering the external voltage, outputting a direct current, a power supply unit, a control unit, a conversion unit, and a switch. a unit, a second rectifying unit, an output unit, a detecting unit and a protection unit, wherein the control unit is configured to start and output a control signal to the switch unit after receiving an external voltage, and the switch unit is configured to receive the control signal and be turned on, the conversion The unit receives the DC current and outputs the DC current to the detecting unit when the switching unit is turned on, and simultaneously supplies an induced current to the second rectifying unit and the power supply unit, and the power supply unit is configured to rectify and filter the induced current to the control unit. Providing a working voltage, the second rectifying unit is configured to rectify and filter the induced current, and output an operating voltage to the working module by the output unit, wherein the detecting unit is configured to receive the DC current to generate a detecting current, and according to the detecting The measuring current generates a detection voltage, and the control unit detects that the detection voltage is too high Stops outputting the control signal, the protection unit is connected to the switching unit, for the direct current in the direct current absorbed is too large and the control unit is not detected when the detection voltage.

The above-mentioned electric equipment converts the external voltage by the switching power supply, and outputs the working voltage for work. Module work. The switching power supply is configured to detect the detection unit, and the control unit detects the detection voltage provided by the detection unit, so that the control unit stops outputting the control signal when the detection voltage is too high, so as to prevent the detection voltage from being damaged by the excessive detection voltage, thereby achieving protection. The purpose of switching power supply. The switch unit is further provided with a protection unit. When the detection current is too large and the control unit does not detect that the detection voltage is too high, the excessive detection current is absorbed to protect the control chip, thereby minimizing the loss of the switching power supply.

100‧‧‧Switching power supply

103‧‧‧First rectification unit

107‧‧‧Control unit

111‧‧‧Conversion unit

115‧‧‧Output unit

119‧‧‧protection unit

201‧‧‧Working module

20a‧‧‧DC input

20c‧‧‧second output

30a‧‧‧Startup

30c‧‧‧Control signal output

R1‧‧‧first resistance

R3‧‧‧ third resistor

D1‧‧‧ diode

D2‧‧‧First Voltage Regulator

101‧‧‧ input unit

105‧‧‧Power supply unit

109‧‧‧Switch unit

113‧‧‧Secondary rectifier unit

117‧‧‧Detection unit

200‧‧‧Electrical equipment

20‧‧‧Transformers

20b‧‧‧first output

30‧‧‧Control chip

30b‧‧‧Working voltage input

30d‧‧‧Detector

R2‧‧‧second resistance

R4‧‧‧fourth resistor

T1‧‧‧ field effect transistor

D3‧‧‧Second voltage regulator

1 is a functional block diagram of a powered device in accordance with a preferred embodiment.

2 is a circuit diagram of a switching power supply of a preferred embodiment.

Referring to FIG. 1, the electrical device 200 includes a switching power supply 100 that receives an external voltage and outputs an operating voltage, and a working module 201 that operates to receive the operating voltage.

The switching power supply 100 includes an input unit 101, a first rectifying unit 103, a power supply unit 105, a control unit 107, a switching unit 109, a conversion unit 111, a second rectification unit 113, an output unit 115, a detection unit 117, and a protection unit 119.

The input unit 101 is for receiving an external voltage and supplying the external voltage to the first rectifying unit 103 and the control unit 107. The external voltage is the mains voltage, such as the standard voltage of 220V in mainland China.

The first rectifying unit 103 is configured to rectify and filter the external voltage to output a direct current, and output the direct current to the converting unit 111.

The control unit 107 is configured to receive the external voltage and operate the power, and output a control signal to the switch unit 109 to control the switch unit 109 to be turned on, so that the conversion unit 111 that receives the DC current output by the first rectifying unit 103 outputs the induced current to The power supply unit 105 and the second rectifying unit 113, The converting unit 111 also transmits the DC current it receives to the detecting unit 117 through the switching unit 109.

The power supply unit 105 is configured to receive the induced current and rectify and filter the same, and then provide an operating voltage to the control unit 107 instead of the external voltage received when the control unit 107 is started.

The second rectifying unit 113 is configured to rectify and filter the induced current, and output the rectified and filtered induced current to the working module 201 through the output unit 115.

The detecting unit 117 is configured to receive the DC current generated by the switching unit 109 by the switching unit 109 to generate a detecting current, and the detecting current is sent by the converting unit 111 to the detecting unit 117 via the switching unit 109. The detecting unit 117 also generates a detection voltage according to the detection current. The control unit 107 is further configured to periodically detect whether the detection voltage is too high. If the detection voltage is too high, the output of the control signal is stopped, the switching unit 109 is turned off, and the conversion unit 111 stops working, that is, there is no DC current through the switch unit 109. The detection unit 117 stops transmitting the detection voltage. When the detecting unit 107 detects the detecting unit 117 again, the detected voltage is not detected, the control unit 107 will re-output the control signal, and the switching unit 109 is turned on, and then the switching power supply 100 enters the next loop.

The protection unit 119 is connected to the switch unit 109 and the detection unit 117 for limiting the voltage between the switch unit 109 and the detection unit 117 to a predetermined value or less. The protection unit 119 is also used to limit the voltage between the switching unit 109 and the control unit 107 below a predetermined value to prevent damage to the control unit 107.

As shown in FIG. 2, it is a circuit diagram of the switching power supply 100 shown in FIG.

The first rectifying unit 103 includes a rectifier bridge and a filter capacitor. The power supply unit 105 includes a current limiting resistor for limiting current, a rectifying diode, and a filter capacitor. The second rectifying unit 113 includes a rectifying diode and a filter capacitor.

The conversion unit 111 includes a transformer 20. The transformer 20 includes a DC input terminal 20a and a first output terminal 20b and a second output 20c. The DC input terminal 20a is connected between the first rectifying unit 103 and the switching unit 109 for receiving the DC current output by the first rectifying unit 103, and transmitting the DC current to the detecting unit 117 through the switching unit 109. The first output terminal 20b is connected to the second rectifying unit 113 for outputting an induced current to the second rectifying unit 113. The second output terminal 20c is connected between the power supply unit 105 and the ground to provide an induced current to the power supply unit 105.

The control unit 107 includes a control wafer 30, a diode D1, and a first resistor R1 and a second resistor R2. The control chip 30 includes a start terminal 30a, an operating voltage input terminal 30b, a control signal output terminal 30c, and a detection terminal 30d. The starting end 30a is connected to the input unit 101 by the first resistor R1 and the diode D1 in sequence, wherein the cathode of the diode D1 is connected to the input unit 101. The operating voltage input terminal 30b is connected to the power supply unit 105. The control signal output terminal 30c is connected to the switch unit 109 by a second resistor R2. The detecting end 30d is connected to the detecting unit 117.

The switching unit 109 includes a field effect transistor T1. The gate of the field effect transistor T1 is connected to the control signal output terminal 30c of the control unit 107, the drain of the field effect transistor T1 is connected to the DC input terminal 20a of the conversion unit 111, and the source of the field effect transistor T1 is connected to the detector. Measurement unit 117.

The detecting unit 117 includes a third resistor R3 and a fourth resistor R4. One of the third resistors R3 is terminated to the source of the field effect transistor T1, and the other end thereof is grounded. One of the fourth resistors R4 is terminated to the source of the field effect transistor T1, and the other end thereof is connected to the detecting end 30d of the control unit 107.

The protection unit 105 includes a first voltage stabilizing diode D2 and a second voltage stabilizing diode D3. The cathode of the first stabilizing diode D2 is electrically connected to the gate of the field effect transistor T1, and its anode is grounded. The cathode of the second stabilizing diode D3 is electrically connected to the source of the field effect transistor T1, and its anode is grounded.

When the electric device 200 needs to work, the external voltage is received by the input unit 101, and the external voltage is sequentially output to the starting end 30a of the control wafer 30 via the diode D1 and the first resistor R1, and the control chip 30 is activated to control The wafer 30 is transferred to the field effect transistor T1 by its control signal output terminal 30d. The control signal is output, and the field effect transistor T1 is turned on. In addition, the external voltage is filtered by the rectifier bridge and filtered by the filter capacitor to become a direct current, and is output to the DC input terminal 20a of the transformer 20. The transformer 20 is turned on by the field effect transistor T1, and the transformer 20 supplies an induced current to the second rectifying unit 113 and the power supply unit 105 through the first output terminal 20b and the second output terminal 20c, and outputs the received DC current to the third. Resistor R3.

The power supply unit 105 rectifies and filters the induced current by the rectifying diode and the filter capacitor, and supplies the operating voltage to the control wafer 30 by the operating voltage input terminal 30b of the control wafer 30. The second rectifying unit 113 rectifies and filters the induced current by the rectifying diode and the filter capacitor, and then supplies the operating voltage to the working module 201 through the output unit 115.

The third resistor R3 receives the DC current to generate a detection current, and the detection current flows through the field effect transistor T1. The third resistor R3 uses the voltage applied to both ends thereof as a detection voltage, and is fed back to the detecting end 30d of the control wafer 30 by the fourth resistor R4. The control chip 30 detects the detection voltage, and when the detection voltage is too high, stops outputting the control signal to the field effect transistor T1 by the control signal output terminal 30c, and the field effect transistor T1 is turned off, so that the third resistor R3 is applied. The voltage of the terminal is zero, and the control chip 30 does not detect the detection voltage, and the control chip 30 re-outputs the control signal to turn on the field effect transistor T1 to enter the next loop.

When the detecting end 30d of the control wafer 30 and the ground terminal are short-circuited, the control wafer 30 will not detect the detected voltage, and thus continuously output the control signal. When the detection current flowing through the field effect transistor T1 and the third resistor R3 is too large, the excessive detection current will damage the field effect transistor T1. At this time, the first Zener diode D2 will absorb the damaged field effect electricity. After the crystal T1 flows to the current of the control wafer 30, the second voltage stabilizing diode D3 absorbs the current flowing to the third resistor R3 to protect the control wafer 30 from damage.

The electric device 200 converts the external voltage by the switching power supply 100 and outputs the operating voltage for the working module 201 to operate. The switching power supply 100 is configured to detect the detection unit 117, and the detection unit 107 detects the detection voltage provided by the detection unit 117, so that the control unit 107 stops when the detection voltage is too high. The control signal is output to achieve the purpose of protecting the switching power supply 100. The switch unit 107 is further provided with a protection unit 119 for absorbing the excessive detection current, protecting the control wafer 30, and thus the loss of the switching power supply 100, when the detection current is too large and the control unit 107 does not detect that the detection voltage is too high. Achieve the minimum.

100‧‧‧Switching power supply

103‧‧‧First rectification unit

107‧‧‧Control unit

111‧‧‧Conversion unit

115‧‧‧Output unit

119‧‧‧protection unit

201‧‧‧Working module

101‧‧‧ input unit

105‧‧‧Power supply unit

109‧‧‧Switch unit

113‧‧‧Secondary rectifier unit

117‧‧‧Detection unit

200‧‧‧Electrical equipment

Claims (11)

A switching power supply includes an input unit for receiving an external voltage, a first rectifying unit for rectifying and filtering an output DC current to an external voltage, a control unit, a conversion unit, a switching unit, a detecting unit, and a protection unit, wherein the control unit is used for After receiving the external voltage, the control signal is started and outputted to the switch unit, and the switch unit receives the control signal and is turned on. The conversion unit receives the DC current and outputs the DC current to the detection unit when the switch unit is turned on. The unit is configured to receive the DC current to generate a detection current, and generate a detection voltage according to the detection current. When the control unit detects that the detection voltage is too high, the control unit stops outputting the control signal; the protection unit is connected to the switch unit, and is used for The direct current is absorbed when the direct current is too large and the control unit does not detect the detected voltage. The switching power supply of claim 1, wherein the switching power supply further comprises a power supply unit, wherein the power supply unit is configured to rectify and filter the induced current to provide an operating voltage to the control unit. The switching power supply of claim 2, wherein the switching power supply further comprises a second rectifying unit and an output unit, wherein the second rectifying unit is configured to rectify and filter the induced current and output an operating voltage by the output unit. . The switching power supply of claim 3, wherein the second rectifying unit comprises a rectifying diode for rectification and a filtering capacitor for filtering. The switching power supply of claim 1, wherein the first rectifying unit comprises a rectifying bridge for rectification and a filter capacitor for filtering. The switching power supply of claim 5, wherein the conversion unit comprises a transformer, the transformer comprising a DC input terminal, a first output terminal and a second output terminal, the input terminal is configured to receive the DC current, the first output The end is configured to output an induced current to the second rectifying unit, the first The two outputs are used to output an induced current to the power supply unit. The switching power supply of claim 6, wherein the control unit comprises a control chip, the control chip includes a starting end, an operating voltage input end, a control signal output end, and a detecting end, and the starting end is configured to receive the external voltage and start The control chip is configured to receive a working voltage provided by the power supply unit, the control signal output end is configured to output a control signal to the switch unit, and the detecting end is configured to receive the detection voltage. The switching power supply of claim 6, wherein the switching unit comprises a field effect transistor, and the gate of the field effect transistor is electrically connected to the control unit for receiving the control signal, and the drain of the field effect transistor It is electrically connected to the conversion unit, and its source is electrically connected to the detection unit. The switching power supply of claim 8, wherein the detecting unit comprises a third resistor and a fourth resistor, one end of the third resistor is connected to the switch unit, the other end is grounded, and one end of the fourth resistor is connected to the control unit, The other end is connected to the switch unit. The switching power supply of claim 8, wherein the protection unit comprises a first voltage stabilizing diode and a second voltage stabilizing diode, and the cathode of the second voltage stabilizing diode is electrically connected to the switching unit, The anode is grounded, and the cathode of the first voltage stabilizing diode is electrically connected to the control unit, and the anode thereof is grounded. The utility model relates to a power consumption device, comprising a switching power supply and a working module. The switching power supply comprises an input unit for receiving an external voltage, a first rectifying unit for rectifying and filtering the external voltage, outputting a direct current, a power supply unit, a control unit, a conversion unit, and a switch. a unit, a second rectifying unit, an output unit, a detecting unit and a protection unit, wherein the control unit is configured to start and output a control signal to the switch unit after receiving an external voltage, and the switch unit is configured to receive the control signal and be turned on, the conversion The unit receives the DC current and outputs the DC current to the detecting unit when the switching unit is turned on, and simultaneously supplies an induced current to the second rectifying unit and the power supply unit, and the power supply unit is configured to rectify and filter the induced current to the control unit. Providing a working voltage, the second rectifying unit is configured to rectify and filter the induced current, and output the operating voltage to the output unit a working module, the detecting unit is configured to receive the DC current to generate a detecting current, and generate a detecting voltage according to the detecting current. When the control unit detects that the detecting voltage is too high, the control unit stops outputting the control signal, and the protection unit and the switch The unit is connected to absorb the direct current when the direct current is too large and the control unit does not detect the detected voltage.