CN203504862U

CN203504862U - High pressure gas discharge lamp ballast

Info

Publication number: CN203504862U
Application number: CN201320374209.5U
Authority: CN
Inventors: 余世伟; 李志峰
Original assignee: Opple Lighting Co Ltd
Current assignee: Opple Lighting Co Ltd
Priority date: 2013-06-27
Filing date: 2013-06-27
Publication date: 2014-03-26
Anticipated expiration: 2023-06-27

Abstract

The utility model relates to a high pressure gas discharge lamp ballast, comprising a double pressure reduction inversion circuit which comprises an inductance element, two switch elements in series connection, and two diodes respectively in parallel connection with the switch elements, the inductance element being in connection with the connecting point of the two switch elements; and a zero cross detection circuit in connection with the inductance element, the zero cross detection circuit comprising a sampling circuit formed by resistive elements, a comparison circuit and a switch circuit which are in sequential connection.

Description

A kind of ballast of high-voltage gas discharging light

Technical field

The utility model relates to the ballast of a kind of ballast of gaseous discharge lamp, particularly a kind of high-voltage gas discharging light.

Background technology

The electric ballast of conventional high-tension gaseous discharge lamp comprises tertiary structure: circuit of power factor correction, and reduction voltage circuit and full bridge inverter, sort circuit complicated structure, cost is expensive.In order to simplify circuit, reduce costs, proposed the ballast of secondary structure that reduction voltage circuit and inverter circuit are combined, Fig. 1 is the schematic diagram of ballast of the high-voltage gas discharging light of secondary structure, comprises circuit of power factor correction 10 and two step-down inverter circuits 20.Adopt secondary structure to reduce volume and the cost of ballast, but share an inductance because of the step-down inverter circuit after simplifying, its zero current detection is difficulty relatively.

Fig. 2 is the schematic diagram of two step-down inverter circuits of high-pressure gas discharge lamp ballast, and wherein L is shared inductance, and VBUS is the voltage after boosting, and J1, J2 are switching tube.This inside circuit contains two reduction voltage circuits, is two BUCK half-bridge inversion circuits, and capacitor C 1, capacitor C 3, HID, L, J1 have formed the first reduction voltage circuit; Capacitor C 2, C3, HID, L, J2 have formed the second reduction voltage circuit, and two step-down inverter circuits are by low-frequency square-wave signal control work, and two reduction voltage circuits are controlled alternation at low-frequency square-wave signal.The operation principle of the two step-down inverter circuits shown in Fig. 1 is as follows:

When input low-frequency square-wave signal is high level, the first reduction voltage circuit work, high-frequency driving signal is distributed to J1; While being low level for low-frequency square-wave signal, the second reduction voltage circuit work, high-frequency driving signal is distributed to J2.When J1 is closed, when J2 disconnects, electric current flows through J1, L, C3, HID, C1, and inductance L is charged; When J1 disconnects, when J2 disconnects, electric current flows through L, C3, HID, C2, diode D2, inductance L electric discharge.

During the second reduction voltage circuit work, when J2 is closed, when J1 disconnects, electric current flows through C2, HID, C3, L, J2, and inductance L is charged; When J2 disconnects, when J1 disconnects, electric current flows through C1, HID, C3, L, diode D1, L electric discharge.

Because two step-down inverter circuits share an inductance, the sense of current that flows through inductance during two reduction voltage circuit turn-on and turn-off is different, detects its zero cross signal difficulty relatively.

summary of the invention

The purpose of this utility model is to solve the existing the problems referred to above of high-pressure gas discharge lamp ballast, and a kind of ballast with reliable inductance zero current detecting circuit is provided.

For achieving the above object, the utility model by the following technical solutions.A ballast for high-voltage gas discharging light, comprising: two step-down inverter circuits, comprise the switch element of two series connection, and two diodes in parallel with described switch element respectively, inductance element, described inductance element is connected with the tie point of switch element; Zero cross detection circuit, connects described inductance element; Described zero cross detection circuit comprises sample circuit, comparison circuit and the switching circuit that resistance element forms, and described sample circuit, comparison circuit and switching circuit are linked in sequence.

Preferably, described sample circuit is the resistance series circuit that a plurality of resistance is composed in series, and described resistance series circuit is connected between the tie point and ground of described switch element.

Preferably, above-mentioned comparison circuit comprises the comparator of two series connection, and wherein, the positive input of a comparator and the reverse input end of another comparator connect and compose the sampled voltage input of comparison circuit.

Preferably, the sampled voltage input of above-mentioned comparator is connected with the tie point of resistance in described resistance series circuit.

Preferably, said switching circuit comprises two switch elements, and one end of each switch element is connected with the output of described each comparator respectively.

Preferably, above-mentioned ballast circuit also comprises a low-frequency square-wave signal generative circuit, and for generation of low-frequency square-wave signal, described low-frequency square-wave signal is as the control signal of described pair of step-down inverter circuit work and the gating signal of described two switch elements.

Zero cross detection circuit of the present utility model is sampled to the voltage of the tie point of two switching tubes in two step-down inverter circuits by resistance series circuit, realizes zero passage detection.Not only easily realize.And the reliability of zero passage detection is high, effectively reduce the noise of ballast and reduced the energy consumption of ballast, make its more stable work reliable.

According to below with reference to accompanying drawing to description of the present utility model, other targets of the present utility model and effectiveness will become apparent, and reader can fully understand the utility model.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of existing high-pressure gas discharge lamp ballast;

Fig. 2 is two step-down inverter circuit schematic diagrames of existing high-pressure gas discharge lamp ballast;

Fig. 3 is according to the zero cross detection circuit schematic diagram of an embodiment of the utility model;

Fig. 4 is according to the zero cross detection circuit schematic diagram of an embodiment of the utility model;

Fig. 5 is according to the zero cross detection circuit schematic diagram of an embodiment of the utility model.

In above-mentioned accompanying drawing, same reference numerals identical, the similar or corresponding element of indication or function.

Embodiment

Below with reference to graphic, by embodiment, describe specific embodiment of the utility model in detail.

The description that Fig. 3 is detailed the zero cross detection circuit of an embodiment of the utility model.With reference to Fig. 3, two step-down inverter circuits 30 comprise switch element J1, switch element J2, capacitor C 1, C2 and C3, diode D1, diode D2, inductance component L 1.Switch element J1 and J2 series connection, capacitor C 1 and C2 series connection, the C1 of the J1 of series connection, J2 and series connection, C2 carry out parallel connection.Direct voltage VBUS is added on the series circuit of J1 and J2 as the input of two step-down inverters.Inductance L 1 and the series connection of HID lamp, be then connected to the tie point A that switch element J1 and J2 connect.Capacitor C 1, capacitor C 3, HID lamp, J1 and inductance component L 1 form the first reduction voltage circuit in two step-down inverter circuits.Capacitor C 2, C3, HID, L1, J2 have formed the second reduction voltage circuit.

As shown in Figure 3, zero cross detection circuit 300, for detection of the current zero-crossing point of described inductance L 1.Zero cross detection circuit 300 is connected with inductance L 1, zero cross detection circuit comprises sample circuit 301, comparison circuit 302 and switching circuit 303, wherein, sample circuit 301 connects inductance L 1 in A point, and sample circuit 301, comparison circuit 302 and switching circuit 303 are linked in sequence.Sample circuit 301 is composed in series resistance series circuit by two resistance R 3 and R4, and the series circuit of resistance R 3 and R4 is connected between the tie point A and ground of switch element J1 and J2, in parallel with switch element J2 and diode D2.

Comparison circuit 302 comprises two comparator U1 and U2, the reverse termination reference level Vref 1 of comparator U1 wherein, the forward termination reference level Vref 2 of comparator U2.The positive input of U1 and the reverse input end of U2 connect and compose the sampled voltage input In of comparison circuit 302, and this input is connected with the tie point B of resistance R 3 in resistance series circuit in sample circuit 301 and R4.Switching circuit 303 comprises switch element J3 and J4, and switch element J3, J4 are connected with the output of comparator U1 and U2 respectively as shown in Figure 3.

With reference to Fig. 3, also comprise that a low-frequency square-wave signal generative circuit 304 is for generation of low-frequency square-wave signal, low-frequency square-wave signal is used for controlling two step-down inverter circuit alternations, and also the while is as the control signal of switching circuit 302, when low-frequency square-wave signal is low level, J3 is closed; When low-frequency square-wave signal is high level, J4 is closed.When low-frequency square-wave drives signal to be high level, the first reduction voltage circuit work, J1 closed and disconnected is controlled in high-frequency drive pulse.When J1 closed and disconnected, the level that A is ordered can change, so the voltage VB that sample resistance B is ordered also can change.J1 disconnects, inductance L 1 electric discharge, when the electric current of inductance L 1 is reduced to zero, A point voltage VA can rise, so B voltage VB also can rise, at this moment detects voltage VB, when VB is greater than Vref1, comparator U1 exports high level, and zero cross detection circuit output high level zero passage detection signal, makes J1 at zero current again conducting.

When low-frequency square-wave drives signal to be low level, the second reduction voltage circuit work, J2 closed and disconnected is controlled in high-frequency drive pulse.Its principle is similar with J1 work, when J2 disconnects, and inductance L 1 electric discharge, when the electric current of inductance L 1 is reduced to zero, A point voltage VA can decline, so when voltage VB is less than Vref2, comparator U2 exports high level, makes J2 at zero current again conducting.The change in voltage that the resistance of resistance R 3 and R4 can be ordered according to the tie point A of J1 and J2 is selected in advance, the voltage VB that B is ordered, and when the first reduction voltage circuit work, when L1 has discharged, the voltage that B is ordered is greater than reference voltage.When the second reduction voltage circuit work, when L1 has discharged, the voltage that B is ordered is less than reference voltage.

As mentioned above, the variation that zero cross detection circuit detects by two comparators the level that in sample circuit, B is ordered just can obtain zero cross signal, and accurately whether the electric current of the inductance L 1 of the two step-down inverter circuits of judgement discharges, and judges the current zero-crossing point of inductance L 1.

The zero cross detection circuit of an embodiment of Fig. 4 the utility model, with reference to Fig. 4, VCC is the direct voltage of chip power supply, R3, R4, R5, R6 are sample resistance, resistance R 3, R4, R5 and R6 sample circuit in series, D1, D2 are fly-wheel diode, and the effect of C3 is filtering, and C1, C2 effect are by VBUS dividing potential drop, every straight-through, hand over.Comparison circuit and switching circuit are realized as single-chip microcomputer U by microcontroller, U can be also the integrated chip that comparator is contained in other inside, Uc is single-chip microcomputer internal comparator, the positive input that wherein 7 pins are comparator, 6 pins are the negative input of comparator, the output that 5 pins are comparator.Q1, Q2 are field effect transistor or other switch element.

When low-frequency square-wave drives signal to be high level, the first reduction voltage circuit work, single-chip microcomputer is effective by programming comparator pin 7 positive inputs, and negative end is for being connected to single-chip microcomputer internal register.The numerical value of internal register is Vref1, and upper pipe Q1 closed and disconnected is controlled in high-frequency drive pulse.When Q1 is closed, L1 is charged, the voltage VA of half-bridge mid point A equals the conduction voltage drop that VBUS(ignores Q1).The ratio of R3, R8, R9 and R10 is set as follows, and when A point voltage VA equals VBUS, guarantees that voltage VB is greater than Vref1, comparator output terminal 5 output high level.When Q1 disconnects, L1 discharges, A point current potential identical with GND (conduction voltage drop of ignoring D2) now, so voltage VB is less than Vref1, and comparator output low level.When L1 electric discharge finishes, VA point voltage can rise, and when voltage VB rises to while being greater than Vref1, comparator output high level, opens switching tube Q1 again.

When low-frequency square-wave drives signal to be low level, the second reduction voltage circuit work, single-chip microcomputer is effective by programming comparator pin 6 negative inputs, and forward end is connected to single-chip microcomputer internal register.The numerical value of internal register is Vref2, and upper pipe Q2 closed and disconnected is controlled in high-frequency drive pulse.When Q2 is closed, L1 is charged, the voltage VA current potential identical with GND (conduction voltage drop of ignoring Q1) of half-bridge mid point A, due to voltage, VB is less than Vref2, comparator output terminal 5 output high level; When Q2 disconnects, L1 discharges, A point current potential identical with VBUS (conduction voltage drop of ignoring D1) now, and due to voltage, VB is greater than Vref1, comparator output low level, on-off switching tube Q2.When L1 electric discharge finishes, VA point voltage can decline, and when voltage VB drops to while being less than Vref2, comparator output high level, opens switching tube Q2 again.

Fig. 5 is another embodiment of zero cross detection circuit of the present utility model, and the embodiment of principle and Fig. 4 is identical, and switching circuit 303 consists of D3, D4, D5, D6, R15, Q3, for the output of gating comparator 302.

Above-described embodiment is exemplary, and does not wish that they limit technical method of the present utility model.Although describe the utility model in detail with reference to preferred embodiment; but be understood by those skilled in the art that; can be in the situation that do not depart from the spirit of the utility model technical method and category and revise or be equal to and replace technical method of the present utility model, these modifications and be equal to the protection category that replacement also belongs to the utility model claims.

Claims

1. the ballast of a high-voltage gas discharging light, comprise: two step-down inverter circuits, switch element (the J1 that comprises two series connection, J2), two diode (D1s in parallel with described switch element (J1, J2) respectively, D2), inductance element (L1), described inductance element (L1) connects with the tie point (A) of described switch element (J1, J2);

Zero cross detection circuit (300), connects described inductance element (L1);

It is characterized in that, described zero cross detection circuit (300) comprises sample circuit (301), comparison circuit (302) and the switching circuit (303) consisting of resistance element, and described sample circuit, described comparison circuit and described switching circuit are linked in sequence.

2. the ballast of high-voltage gas discharging light according to claim 1, it is characterized in that, described sample circuit is the resistance series circuit that a plurality of resistance is composed in series, and described resistance series circuit is connected between the tie point (A) and ground of described switch element (J1, J2).

3. the ballast of high-voltage gas discharging light according to claim 2, it is characterized in that, described comparison circuit (302) comprises the comparator (U1 of two series connection, U2), wherein, the reverse input end of the positive input of a comparator (U1) and another comparator (U2) connects and composes the sampled voltage input (In) of comparison circuit (302).

4. the ballast of high-voltage gas discharging light according to claim 3, is characterized in that, the sampled voltage input (In) of described comparator is connected with the tie point (B) of resistance in described resistance series circuit.

5. the ballast of high-voltage gas discharging light according to claim 3, it is characterized in that, described switching circuit (303) comprises two switch elements (J3, J4), one end of each switch element connects with the output of described each comparator (U1, U2) respectively.

6. the ballast of high-voltage gas discharging light according to claim 5, it is characterized in that: also comprise a low-frequency square-wave signal generative circuit (304), for generation of low-frequency square-wave signal, described low-frequency square-wave signal is as the control signal of described pair of step-down inverter circuit work and the gating signal of described two switch elements (J3, J4).