CN2394377Y

CN2394377Y - Time delayed protector for bridge inverter

Info

Publication number: CN2394377Y
Application number: CN 99245651
Authority: CN
Inventors: 张玉清
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-09-22
Filing date: 1999-09-22
Publication date: 2000-08-30
Anticipated expiration: 2009-09-22

Abstract

The utility model relates to a time delayed protector for bridge inverters. The time delayed protector is composed of a protective circuit and a preheating circuit. The time delayed protector is installed between an upper and a lower bridge circuits of a bridge inverter. The protective circuit is composed of a voltage stabilizing tube DW, a trimming resistor RV1, resistors R7 to R9, transistors BG3, BG4 and a capacitor C4, wherein, the voltage stabilizing tube DW is connected between two transistors of the bridge inverter. The preheating circuit is composed of a capacitor C4, resistors R5 to R8, and transistor BG5, BG3, wherein, the capacitor C4 receives the signals of a triggering circuit, and is connected between the voltage stabilizing tube DW and the resistor R5 which is the base pole of the transistor BG5. The utility model has the advantages of low cost, small volume, and preheating and protection functions.

Description

The bridge-type inverter delay protection device

The utility model relates to the electronic product that has bridge-type inverter, specifically a kind of delay protection device that is applied to have on the bridge-type inverter electronic product.

In the prior art, the electronic product of selling on the market that has inverter is a lot, as electric ballast, electronic welding machine, switch transformer, electromagnetic stove, ultrasonic wave driving power, inverter power supply etc., have fatal deficiency mostly: the life-span that is exactly bridge-type inverter itself is short, owing to the defective in the design, two high power valves damage because of overcurrent under accidental common conducting situation great majority in the short time of use.As: use electric ballast, because of the bridge-type inverter in most of electric ballasts is not with preheating device, there is not preheat function during startup, so the cold start meeting causes the coating of metal oxides sputter on the filament surface of lamp tube ends fast, cause lamp tube ends to be turned black too early, obviously shortened the useful life of fluorescent tube.

In order to overcome above-mentioned deficiency, the utility model provides a kind of cost low, and volume is little, has the bridge-type inverter delay protection device of preheating protection function.

For achieving the above object, the technical solution of the utility model is: comprise transistor, electric capacity, resistance, it is characterized in that: be made up of protective circuit and preheat circuit, be installed in as the bridge-type inverter of exporting up and down between the bridge circuit;

Described protective circuit is by voltage-stabiliser tube DW, semifixed resistor RV1, resistance R 7～R9, transistor BG3, BG4 and capacitor C 2 are formed, described voltage-stabiliser tube DW negative pole connects the emission E point very of the transistor BG1 of bridge-type inverter, its positive pole connects the current collection F point very of another transistor BG2 of bridge-type inverter, described semifixed resistor RV1 is parallel to voltage-stabiliser tube DW two ends, its feather key connects the base stage of transistor BG4 through resistance R 9, the emitter of described transistor BG4 links to each other with the anodal F point of voltage-stabiliser tube DW, its collector electrode connects the base stage of transistor BG3 after capacitor C 5 and resistance R 8 parallel connections, described transistor BG3 base stage connects the base stage of its emitter and transistor BG1 through resistance R 7, and described E point signal is from the emitter of transistor BG1;

Described preheat circuit is made up of capacitor C 4, resistance R 5～R8, transistor BG5, BG3, wherein accept the E end of the capacitor C 4 positive termination voltage-stabiliser tube DW of circuits for triggering signal, negative terminal is through the base stage of resistance R 5 to transistor BG5, described transistor BG5 emitter connects the F end of voltage-stabiliser tube DW, and its collector electrode is connected to the base stage of transistor BG3 through resistance R 8.

Described bridge-type inverter is self-excitation, its sharp half-bridge or full-bridge inverter; Described is electric ballast and fluorescent tube, switch transformer, electronic welding machine, ultrasonic wave driving power, inverter power supply or electromagnetic stove etc. with bridge-type inverter as the electronic product of exporting; Described protective circuit and preheat circuit can be resolution element, also can be integrated circuit.

The utlity model has as above advantage:

The utility model has increased by tens electronic components and (as has been applied to electric ballast in original circuit, about the about yuan of its cost), can overcome the accidental common conducting phenomenon of two high power valves effectively, the life-span that has bridge-type inverter can be prolonged exponentially, and when starting, has a preheat function, can be applicable on the electronic products such as electric ballast and fluorescent tube, switch transformer, electronic welding machine, ultrasonic wave driving power, inverter power supply, electromagnetic stove, have social benefit widely.

Description of drawings:

Accompanying drawing 1 is the utility model electrical schematic diagram.

Below in conjunction with accompanying drawing structure of the present utility model and operation principle are described in further detail:

As shown in Figure 1, be applied in a embodiment on the electric ballast for the utility model.Power supply is added in A, the B two ends, after the bridge rectifier rectification via diode D1～D4 composition, by capacitor C 1～C2, the power factor correction filter filtering that diode D5～D7 and resistance R 1 are formed, in C, 2 of D produce dc pulse moving voltage, resistance R 2 for circuits for triggering, capacitor C 3, bidirectional diode DR1 and bridge-type inverter use, described bridge-type inverter is the auto-excitation type half-bridge inverter, by transistor BG1～BG2, base stage current-limiting resistance R3, R4, feedback transformer T1, choking coil L1, resonant capacitance C8, alternating current path capacitor C6～C7 and support flourescent lamp pipe G1 form; After described preheat circuit was installed in the circuits for triggering of reception from bridge rectifier, power factor correction filter signal, described protective circuit was installed in the bridge-type inverter of preheat circuit and conduct output up and down between the bridge circuit;

Described protective circuit is by voltage-stabiliser tube DW, semifixed resistor RV1, resistance R 7～R9, transistor BG3, BG4 and capacitor C 5 are formed, the emission that described voltage-stabiliser tube DW negative pole meets transistor BG1 is the E point very, the current collection that its positive pole meets transistor BG2 is the F point very, described semifixed resistor RV1 is parallel to voltage-stabiliser tube DW two ends, its feather key connects the base stage of transistor BG4 through resistance R 9, the emitter of described transistor BG4 links to each other with the anodal F point of voltage-stabiliser tube DW, its collector electrode connects the base stage of transistor BG3 after capacitor C 5 and resistance R 8 parallel connections, described transistor BG3 base stage connects the base stage of its emitter and transistor BG1 through resistance R 7, and described E point signal is from the emitter of transistor BG1;

The utility model operation principle is as follows:

Protective circuit:

When transistor BG2 conducting, there is electric current to flow through voltage-stabiliser tube DW two ends; direct voltage about 1～1.5 volt of its two ends generation; the E point is for just; the F point is for negative; this voltage one side is as the sampling voltage of transistor BG4 base stage; on the other hand as transistor BG4; the supply voltage of BG5 uses; suitably adjust the position of the feather key of semifixed resistor RV1; transistor BG4 is just ended at transistor BG1; conducting during transistor BG2 conducting handing-over (is annotated: if resistance R V1 adjusted conference transistor BG2 ON time is shortened; power output reduces; resistance R V1 adjusts too small meeting does not shield protective circuit); at this moment the F negative electricity of ordering is through transistor BG4; resistance R 8 is added to the base stage of transistor BG3; make transistor BG3 conducting; thereby make the base stage of transistor BG1 and the voltage of emitter approach 0 volt, guarantee that BG1 ends more reliably.The characteristics of this protective circuit maximum are: when the BG1 conducting whenever; if BG2 conducting; can both force transistor BG1 to enter cut-off state immediately by voltage-stabiliser tube DW, transistor BG4, BG3, preventing from especially effectively to arrive in the common conducting of transistor BG1, BG2 burns out.

Preheat circuit:

The voltage at the two ends of capacitor C4 equals 0 volt when electric ballast rigidly connects energize, the upper end G point voltage that is equivalent to resistance R 5 equals the E point voltage of voltage-stabiliser tube DW, this voltage is added to the base stage of transistor BG5 by resistance R 5, make its conducting, the conducting of transistor BG5 makes transistor BG3 conducting by R8 again, transistor BG3 conducting forces BG1 to end again, its result can make BG1 ON time in each cycle of oscillation very short, at this moment inverter (transistor BG1, BG2) it is just very little to export to the power of load fluorescent tube, therefore the filament of fluorescent tube can not be subjected to the impact of big electric current and enter preheat mode, the negative electricity of the F end points of voltage-stabiliser tube DW charges to capacitor C 4 through R5 by the base stage of resistance R 6 and transistor BG5 simultaneously, the G point voltage of resistance R 5 upper ends is descended gradually along with the increase of time, by transistor BG5, the BG3 effect increases the ON time of BG1 in each cycle of oscillation gradually, the power of exporting to fluorescent tube simultaneously also increases gradually, and the temperature of tube filament also raises gradually.When the G point voltage drops to below 0.6 volt, BG5 ends, warm finishes, at this moment the ON time of BG1 in each cycle of oscillation is near 50%, at this moment inverter power output maximum, fluorescent tube enters normal luminance, if suitably select the resistance of the capacity of capacitor C 4 and resistance R 5, R6, can adjust the warm-up time and the temperature of tube filament.

Bridge-type inverter described in the utility model also can be independent-excited half-bridge or full-bridge inverter, or the auto-excitation type full-bridge inverter.

Protective circuit part of the present utility model can also be applied in switch transformer, electronic welding machine, ultrasonic wave driving power, inverter power supply and electromagnetic stove etc. and have on the electronic product of inverter.

Protective circuit described in the utility model and preheat circuit can be resolution element, also can be integrated circuit.

Claims

1. a bridge-type inverter delay protection device comprises transistor, electric capacity, resistance, it is characterized in that: be made up of protective circuit and preheat circuit, be installed in as the bridge-type inverter of exporting up and down between the bridge circuit;

Described protective circuit is by voltage-stabiliser tube DW, semifixed resistor RV1, resistance R 7～R9, transistor BG3, BG4 and capacitor C 5 are formed, described voltage-stabiliser tube DW negative pole connects the emission E point very of the transistor BG1 of bridge-type inverter, its positive pole connects the current collection F point very of another transistor BG2 of bridge-type inverter, described semifixed resistor RV1 is parallel to voltage-stabiliser tube DW two ends, its feather key connects the base stage of transistor BG4 through resistance R 9, the emitter of described transistor BG4 links to each other with the anodal F point of voltage-stabiliser tube DW, its collector electrode connects the base stage of transistor BG3 after capacitor C 5 and resistance R 8 parallel connections, described transistor BG3 base stage connects the base stage of its emitter and transistor BG1 through resistance R 7, and described E point signal is from the emitter of transistor BG1;

2. according to the described bridge-type inverter delay protection device of claim 1, it is characterized in that: described bridge-type inverter is self-excitation, its sharp half-bridge or full-bridge inverter.

3. according to the described bridge-type inverter delay protection device of claim 1, it is characterized in that: described is electric ballast and fluorescent tube, switch transformer, electronic welding machine, ultrasonic wave driving power, inverter power supply or electromagnetic stove with bridge-type inverter as the electronic product of exporting.

4. according to the described bridge-type inverter delay protection device of claim 1, it is characterized in that: described protective circuit and preheat circuit can be resolution element, also can be integrated circuit.