CN204649798U

CN204649798U - One prevents aircraft bombing circuit

Info

Publication number: CN204649798U
Application number: CN201520242319.5U
Authority: CN
Inventors: 陈显林; 彭解红; 王安素; 王仲; 蔡海强; 陈松; 高红宝
Original assignee: ROLED OPTO ELECTRONICS (SHANGHAI) CO Ltd
Current assignee: ROLED OPTO ELECTRONICS (SHANGHAI) CO Ltd
Priority date: 2015-04-20
Filing date: 2015-04-20
Publication date: 2015-09-16
Anticipated expiration: 2025-04-20

Abstract

The utility model discloses one and prevent aircraft bombing circuit, it is characterized in that this circuit comprises: the output terminal DRV of bridge rectifier circuit DB1, transformer T1, diode D1, diode D2, field effect transistor transistor Q1, electric capacity C2, electric capacity C3, electric capacity C4, resistance R2, resistance R1, electric capacity C1, diode D3, pfc circuit.This circuit energy available protecting PFC-MOSFET, when adding high pressure, evading stray capacitance gate pole stored charge and exceeding PFC-MOSFET gate voltage stress.Thus protection field effect transistor transistor Q1, avoid aircraft bombing.

Description

One prevents aircraft bombing circuit

Technical field

The utility model relates to LED technical field of measurement and test, is specifically related to one and prevents Switching Power Supply after encapsulating, the circuit of aircraft bombing when bringing light fixture to carry out Hi-pot test.

Background technology

The large multi-band PFC of LED streetlamp power source in the market, needs encapsulating (epoxy resin or polyurethane pouring sealant), in order to do IP66 waterproof.Street lamp is capacitive load, introduces stray capacitance, also impels stray capacitance to increase further after encapsulating.Due to the increase of stray capacitance, when carrying out High-Voltage Insulation test to it, go in the circuit that noise can be coupled to by stray capacitance, have impact on the key parameter of test, cause the voltage stress that can bear beyond PFC-MOSFET, the aircraft bombing of PFC part occurs.Therefore, when Switching Power Supply brings light fixture to carry out Hi-pot test after encapsulating, preventing aircraft bombing phenomenon is letter technical matters to be solved.

Summary of the invention

The utility model proposes one and prevent aircraft bombing circuit, its circuit structure is simple, cheap for manufacturing cost, and concrete technical scheme is as follows: this circuit comprises bridge rectifier circuit DB1, the negative sense output head grounding of DB1; The positive input of the forward output terminal of DB1 and one end of transformer T1 and diode D1 is public to be connected, and the drain electrode of the other end of transformer T1 and the positive input of diode D2, field effect transistor transistor Q1, one end of electric capacity C2 is public is connected; The other end of electric capacity C2, the source ground of field effect transistor transistor Q1; One end of the reverse input end of diode D1, the reverse input end of diode D2, electric capacity C3, the public connection in one end of electric capacity C4; The other end of electric capacity C3, the other end ground connection GND of electric capacity C4; One end of the grid of field effect transistor transistor Q1, one end of resistance R2, resistance R1, one end of electric capacity C1, the public connection of positive input of diode D3; The other end of resistance R2, the other end ground connection of electric capacity C1; The public connection of reverse input end of the output terminal DRV of pfc circuit, the other end of resistance R1, diode D3; The GND of pfc circuit holds ground connection.

In further embodiment of the present utility model, described electric capacity C3 is polar capacitor, and the reverse input end of the positive pole of described electric capacity C3 and the reverse input end of diode D2, diode D1, one end of electric capacity C4 is public is connected, another pole ground connection of electric capacity C3.

In further embodiment of the present utility model, field effect transistor transistor Q1 drain electrode is connected with the reverse input end of a voltage stabilizing diode, and the positive input of voltage stabilizing diode is connected with the source electrode of field effect transistor transistor Q1.

In further embodiment of the present utility model, field effect transistor transistor Q1 is PFC power switch MOSFET.

In further embodiment of the present utility model, the capacitance of the stray capacitance Cm that the capacitance of electric capacity C1 and the S pole of field effect transistor transistor Q1 and casing are formed matches.

Beneficial effect

This patent makes PFC-MOSFET gate voltage be no more than voltage stress setting value, to protect PFC-MOSFET, thus avoids PFC-MOSFET puncture short and aircraft bombing phenomenon occurs.Compared with prior art, advantage energy available protecting PFC-MOSFET of the present invention, when adding high pressure, evading stray capacitance gate pole stored charge and exceeding PFC-MOSFET gate voltage stress.Realize cost very cheap, implementation method is simply effective.

Accompanying drawing explanation

Fig. 1 is for preventing aircraft bombing circuit.

Embodiment

Be illustrated in figure 1 one and prevent aircraft bombing circuit, its circuit structure is simple, cheap for manufacturing cost, and concrete technical scheme is as follows: this circuit comprises bridge rectifier circuit DB1, the negative sense output head grounding of DB1; The positive input of the forward output terminal of DB1 and one end of transformer T1 and diode D1 is public to be connected, and the drain electrode of the other end of transformer T1 and the positive input of diode D2, field effect transistor transistor Q1, one end of electric capacity C2 is public is connected; The other end of electric capacity C2, the source ground of field effect transistor transistor Q1; One end of the reverse input end of diode D1, the reverse input end of diode D2, electric capacity C3, the public connection in one end of electric capacity C4; The other end of electric capacity C3, the other end ground connection GND of electric capacity C4; One end of the grid of field effect transistor transistor Q1, one end of resistance R2, resistance R1, one end of electric capacity C1, the public connection of positive input of diode D3; The other end of resistance R2, the other end ground connection of electric capacity C1; The public connection of reverse input end of the output terminal DRV of pfc circuit, the other end of resistance R1, diode D3; The GND of pfc circuit holds ground connection.Field effect transistor transistor Q1 is PFC power switch MOSFET.

Because LED streetlamp power source all needs encapsulating, thus get involved stray capacitance, when adding high pressure, having gone in the circuit that will be coupled to by stray capacitance, causing the voltage stress that can bear beyond PFC-MOSFET, making PFC-MOSFET puncture short.In stray capacitance, a series connection electric capacity, utilizes principle of capacitive divider, reduces PFC-MOSFET gate voltage when High-Voltage Insulation is tested, thus protects PFC-MOSFET.

Specific works principle is as follows, and with reference to Fig. 1, when on encapsulating Switching Power Supply band, light fixture does high pressure resistant test, the voltage that input and output apply just all is equivalent to be applied between input over the ground, at this moment just require to input can bear over the ground higher withstand voltage.This just proposes higher requirement to the resistance to pressure of field effect transistor transistor Q1, must can bear this higher pressure reduction.Principle according to electric charge accumulates in electric capacity: Q=C*U learns, electric capacity and voltage are inversely proportional to, and are namely that Ciss/Cm and voltage are inversely proportional to.Wherein Ciss is field effect transistor transistor Q1 input capacitance, Cm be the S pole of field effect transistor transistor Q1-MOSFET and casing stray capacitance, be the stray capacitance that medium epoxy resin embedding adhesive, polyurethane pouring sealant or organic silica gel and Mai La insulating trip are formed.In order to protect field effect transistor transistor Q1, reducing the Vgate voltage of field effect transistor transistor Q1, the input capacitance Ciss of field effect transistor transistor Q1 will be strengthened.So a scene effect pipe transistor Q1 gate pole electric capacity C1 in parallel, to increase the capacitance of input capacitance Ciss.When carrying out High-Voltage Insulation test, field effect transistor transistor Q1-MOSFET gate pole surge voltage effectively can be reduced, thus protection field effect transistor transistor Q1, avoid aircraft bombing.

The above embodiment only have expressed preferred implementation of the present utility model, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the utility model the scope of the claims and embodiment.It should be pointed out that for the person of ordinary skill of the art, without departing from the concept of the premise utility, can also make some distortion and improvement, these all belong to protection domain of the present utility model.

Claims

1. prevent an aircraft bombing circuit, it is characterized in that: this circuit comprises bridge rectifier circuit DB1, the negative sense output head grounding of DB1; The positive input of the forward output terminal of DB1 and one end of transformer T1 and diode D1 is public to be connected, and the drain electrode of the other end of transformer T1 and the positive input of diode D2, field effect transistor transistor Q1, one end of electric capacity C2 is public is connected; The other end of electric capacity C2, the source ground of field effect transistor transistor Q1; One end of the reverse input end of diode D1, the reverse input end of diode D2, electric capacity C3, the public connection in one end of electric capacity C4; The other end of electric capacity C3, the other end ground connection GND of electric capacity C4; One end of the grid of field effect transistor transistor Q1, one end of resistance R2, resistance R1, one end of electric capacity C1, the public connection of positive input of diode D3; The other end of resistance R2, the other end ground connection of electric capacity C1; The public connection of reverse input end of the output terminal DRV of pfc circuit, the other end of resistance R1, diode D3; The GND of pfc circuit holds ground connection.

2. circuit as claimed in claim 1, is characterized in that: described electric capacity C3 is polar capacitor, and the reverse input end of the positive pole of described electric capacity C3 and the reverse input end of diode D2, diode D1, one end of electric capacity C4 is public is connected, another pole ground connection of electric capacity C3.

3. circuit as claimed in claim 2, is characterized in that: field effect transistor transistor Q1 drain electrode is connected with the reverse input end of a voltage stabilizing diode, and the positive input of voltage stabilizing diode is connected with the source electrode of field effect transistor transistor Q1.

4. circuit as claimed in claim 3, is characterized in that: field effect transistor transistor Q1 is PFC power switch MOSFET.

5. circuit as claimed in claim 4, is characterized in that: the capacitance of the stray capacitance Cm that the capacitance of electric capacity C1 and the S pole of field effect transistor transistor Q1 and casing are formed matches.