TW200818987A - Full bridge protection circuit and multi-lamp driving circuit using the same - Google Patents

Abstract

A full bridge protection circuit used in a multi-lamp driving circuit comprises a controlling unit, a full bridge unit, and a detection circuit. The controlling unit has an input terminal and an output terminal, and the output terminal of the controlling unit is for outputting a controlling signal. An input terminal of the full bridge unit coupled to the output terminal of the controlling unit is for receiving the controlling signal. The detection circuit couples to the input terminal of the full bridge unit and the input terminal of the controlling unit. When the detection circuit detects the controlling signal received by the input terminal of the full bridge unit is abnormal, the detection circuit changes the voltage level of the input terminal of the controlling unit, such that the controlling unit cease to output the controlling signal accordingly.

Description

200818987W3198PA • EMBODIMENT DESCRIPTION: TECHNICAL FIELD The present invention relates to the technical field of a multi-lamp driving circuit, and more particularly to a full-bridge protection circuit and a multi-lamp driving circuit using the same. [Prior Art] Please refer to FIG. 1 , which shows a conventional multi-lamp driving circuit (intended. As shown in FIG. 1 , the multi-lamp driving circuit 100 is used to drive a plurality of lamps L and tubes L is, for example, a Cold Cathode Fluorescent Lamp (CCFL). The multi-lamp driving circuit WO includes a main control unit 110, a first full-bridge conversion unit 120a, a first transformer 130, and a second full-bridge conversion unit 120b. The second transformer 14 〇 and the two feedback circuits 150 and 160. In addition, the multi-lamp driving circuit 100 of FIG. 1 is described by taking a general dual-drive converter architecture as an example. That is, the main control unit 110, The first full I bridge conversion unit 120a, the first transformer 130 and the feedback circuit 150 are disposed on a main board, and the second full bridge conversion unit 120b, the second transformer 14 and the feedback circuit 160 It is disposed on another slave board S. The main control unit 110 is, for example, a Pulse Width Modulation (PWM) controller for generating control signals S1~S4. Under normal operation, the main unit Control unit 11〇 control signal S1~S4 Wires and the like by the transfer registers, respectively, transmitted to the main circuit board and the sub-circuit 6 Μ

20081 § 987 Remuneration PA board S on multiple full bridge conversion units. As shown in FIG. 1, the control signals si to S4 are transmitted to the first full bridge conversion unit 12A, and the autonomous circuit board is transferred to the second full bridge on the sub-board S by the connector and the cable. Conversion unit 120b. The two full-bridge conversion units 12〇& and 120b each have four transistor switches τ (not shown) for receiving the corresponding control signals S1 S S4 and repeatedly turning on and off, thereby generating an AC drive signal, and After being clamped by the transformers 13A and 140, the coupled lamp tube 1 is input to drive its illumination. The feedback circuits 150 and 160 use a plurality of diodes and resistors to detect the tube current, and (: generate a feedback signal to the main control unit 110. However, in the process of mass production, two pieces are often caused by the operation relationship. The assembly line between the boards generates an assembly error. At this time, the control signals S1 to S4 cannot be transferred to the respective full-bridge conversion units; for example, the second full-bridge on the sub-board S, and the four units of the unit 12〇b The crystal may not receive the normal control signals 51~34 for the fixed square wave, but the situation where the signal is connected to the f signal high (low) level. So, the full bridge conversion, ^ will be possible Overload or other factors cause the transistor or fuse to burn '鲛 and transfer to other groups of full-bridge conversion unit control signals S1~S4. At this time, 'other full-bridge conversion units will follow an abnormality or travel 5 The problem not only greatly affects the quality of the product, but also makes it difficult to carry out the subsequent maintenance work, because it is impossible to know exactly where the abnormality is located and solve the problem of the cause in the manufacturing process.

200818987, W3198PA ' SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a full bridge protection circuit and a plurality of lamp drive circuits using the same. The detection circuit in the full bridge protection circuit is mainly used to detect whether the control signal received by the corresponding full bridge conversion unit or the generated driving signal is abnormal, and then the main control unit stops operating. In this way, when a group of full-bridge conversion units is damaged, it is possible to protect other groups of full-bridge conversion units from abnormality or damage. According to an object of the present invention, a multi-lamp driving circuit for driving a plurality of lamps is proposed. The multi-lamp driving circuit comprises a main control unit, a first full bridge conversion unit, a first transformer, a second full bridge conversion unit, a second transformer and a detection circuit. The main control unit has an input end and an output end, and the output end of the main control unit is used for outputting a control signal. The input end of the first full bridge conversion unit is coupled to the output end of the main control unit to receive the control signal. The primary side of the first transformer is coupled to the output end of the first full bridge conversion unit, and the secondary side of the first transformer is coupled to one of the lamps of one of the lamps. The input end of the second full bridge conversion unit is connected to the output of the main control unit to receive the control signal. The first side of the second transformer is coupled to the output end of the second full-bridge conversion unit, and the second side of the second transformer is coupled to the other end of the lamp. The detection circuit is coupled to the first or second full-bridge conversion unit. The input end is coupled to the input end of the main control unit. When the detecting circuit detects that the control signal received by the input end of the first or second full-bridge conversion unit is abnormal, the detecting circuit changes the input end of the main control unit. The potential is such that the main control unit stops outputting the control signal. According to the object of the present invention, a full bridge protection circuit is proposed. The full bridge protection circuit is applicable to a multi-lamp driving circuit, and includes a main control unit and a full bridge.

200818987 is called 8PA • conversion unit and detection circuit. The main control unit has an input end and an output end, and an output end of the main control unit is used for outputting a control signal. The input end of the full bridge conversion unit is coupled to the output of the main control unit to receive the control signal. The detection circuit is coupled to the input end of the full bridge conversion unit and the input end of the main control unit. When the detection circuit detects that the control signal received by the input end of the full bridge conversion unit is abnormal, the detection circuit changes the potential of the input end of the main control unit, so that the main control unit stops outputting the control signal. In accordance with the purpose of the present invention, a full bridge protection circuit is proposed. The full bridge protection circuit is suitable for a multi-lamp drive circuit and includes a main control unit, a full-bridge conversion unit, and a detection circuit. The main control unit has an input. The full bridge conversion unit is coupled to the main control unit, and includes a first transistor, a second transistor, a third transistor, and a fourth transistor, and the first and second transistors are connected in series, and the third and fourth transistors are connected in series . The main control unit controls the first to fourth transistors to generate a driving signal. The detecting circuit is coupled to the driving signal and the input end of the main control unit. When the detecting circuit detects that the driving signal is abnormal, the detecting circuit changes the potential of the input end of the main control unit, so that the main control unit stops the control. (1) The first to fourth transistors generate driving signals. According to the purpose of the present invention, a multi-lamp driving circuit for driving a plurality of lamps is provided. The multi-lamp driving circuit includes a main control unit, a full-bridge conversion unit, a transformer, and a detection circuit: the main control unit has an input end, the full bridge conversion unit is coupled to the main control unit, and includes a first transistor, a second transistor, a third transistor, and a fourth transistor, and the first and the second The transistors are connected in series, and the third and fourth transistors are connected in series. The main control unit controls the first to fourth transistors to generate a driving signal. The primary side of the transformer is coupled to the full bridge conversion unit.

W3198PA 200818987, the element receives the driving signal, and the secondary side of the transformer is coupled to one of the lamps. The detecting circuit is coupled to the driving signal and the input end of the main control unit. When the detecting circuit detects that the driving signal is abnormal, the detecting circuit changes the potential of the input end of the main control unit, so that the main control unit stops the control. The first to fourth transistors generate drive signals. According to an object of the present invention, a multi-lamp driving circuit for driving a plurality of lamps is proposed. The multi-lamp driving circuit includes a main control unit, a full-bridge conversion unit, a transformer, and a detection circuit. The main control unit has an input end and an output end, and the output end of the main control unit is used to output a control signal. The input end of the full bridge conversion unit is coupled to the output end of the main control unit to receive the control signal. The primary side of the transformer is coupled to the output end of the full bridge conversion unit, and the secondary side of the transformer is coupled to one of the lamps of one of the lamps. The detection circuit is coupled to the input end of the full bridge conversion unit and the input end of the main control unit. When the detecting circuit detects that the control signal received by the input end of the full bridge converting unit is abnormal, the detecting circuit changes the potential of the input end of the main control unit, so that the main control unit stops outputting the control signal. The above described objects, features, and advantages of the present invention will become more apparent from the aspects of the preferred embodiments of the invention. The figure is a schematic view of a multi-lamp driving circuit in accordance with a first embodiment of the present invention. The multi-lamp driving circuit 200 is used to drive more

200818987 8PA lamp L, and includes a master control element 210, a brother-full bridge conversion unit 220a, a first transformer 230, a second full bridge conversion unit 220b, a second transformer 24A, and a detection circuit 250. For example, the multi-lamp driving circuit 2 is also exemplified by a dual-drive converter structure, that is, two full-bridge converting units 220a and 220b are respectively disposed on two circuit boards (not shown). The detection circuit 25 is coupled to the second full-bridge conversion unit 220b on the sub-board to take a comparison with the conventional ones and explain how to exert the protection effect. In addition, the conventional feedback circuit also omits the illustration. (The main control unit 210 has an input terminal 211 and an output terminal 212, and the output terminal 212 of the main control unit 210 is configured to output a control signal S. The main control unit 210 has a plurality of pins depending on the full bridge conversion unit used. As an output end, the control signals of the pins are output to the input terminals of the corresponding transistor switching elements of the full bridge conversion units. The input end 221a of the first full bridge conversion unit 220a is coupled to the output end of the main control unit 210. 212, to receive the control signal S. The input end 221b of the second full-bridge conversion unit 220b is also coupled to the output terminal 212 of the main control unit 210 to receive the control signal S. The detection unit (250 is coupled to the second full The input end 221b of the bridge conversion unit 220b is coupled to the input end 211211 of the main control unit 210. In addition, the primary side (P) of the first transformer 230 is coupled to the output end 222a of the first full bridge conversion unit 220a, first The secondary side (4) of the transformer is coupled to the lamp, one end of the tube L. The primary side (P) of the second transformer 240 is coupled to the output end 222b of the second full bridge conversion unit 220b, and the secondary side of the second transformer 240 (s Lightly connect the other end of the lamp L. The function of the detecting circuit 250 If for detecting a second full bridge converter 11,200,818,987

W3198PA WV u — ^ Ύ ^ ^ \JA. Λ. 改变 When the control signal s received by the input terminal 221b of the unit 220b is abnormal (as caused by a conventional wiring error), the potential of the input terminal 211 of the main control unit 210 is changed. The pWM control chip inside the main control unit 210 stops outputting the control signal s according to the potential change of the input terminal 211, thereby ensuring that if the second full bridge conversion unit 220b is damaged, the other components of the multi-lamp driving circuit 2 For example, the first full bridge conversion unit 22A does not receive the abnormal control signal S. The circuit architecture and operation of the detection circuit 250 are described in detail below with reference to the drawings. ^ Γ Please refer to Fig. 3, which is a circuit diagram of the detecting circuit 25A of Fig. 2. The detecting unit 250 includes a charging and discharging unit 251 and a switching unit 252. As shown in Fig. 3, the charge and discharge unit 251 includes a diode D, a first resistor R1, a first capacitor C1, a second capacitor C2, a second resistor R2, and an NMOS transistor Q1. The first resistor R1 and the first capacitor C1 are connected in parallel between a ground GND and a cathode of the diode D. The second capacitor C2 is coupled between the anode of the diode D and the first end of the second resistor R2. The second end of the second resistor r2 is coupled to an operating voltage Vcc. The gate v of the NMOS transistor Q1 is used to lightly connect the input end 221b of the second full bridge conversion unit 220b in FIG. 2. The source and the drain of the NMOS transistor Q1 are respectively coupled to the ground GND and the second resistor R2. The first end. The switching unit 252 includes an NMOS transistor Q2, an NMOS transistor Q3, and a third resistor R3. The gate and the source of the NMOS transistor Q2 are coupled to the cathode of the diode D and the ground GND, respectively. The gate and the source of the NMOS transistor Q3 are respectively connected to the drain of the NMOS transistor Q2 and the ground GND. The drain of the NMOS transistor Q3 is used to couple the main control in FIG.

200818987 job PA • Input 211 of unit 210. The third resistor R3 is coupled between the operating voltage Vcc and the gate of the NMOS transistor Q3. When the control signal S received by the input end 221b of the second full-bridge conversion unit 220b is a normal square wave, the NMOS transistor Q1 is accordingly turned on and off to make the current pass through the second resistor R2, the second capacitor C2, and the second. The first capacitor C1 is charged by the polar body D. That is, the cathode potential of the diode d rises to a fixed level. At this time, the NM0S transistors Q2 and Q3 are turned on and off, respectively, and the drain of the NMOS transistor Q3 is maintained at a high level. [However, when the control signal S received by the input terminal 221b of the second full-bridge conversion unit 220b is abnormal, such as signal blanking or fixed high (low) level, that is, the NMOS transistor Q1 will not be turned on and off repeatedly. The second capacitor will short-circuit or isolate the DC signal at the solid state. At this time, the first capacitor C1 will be discharged by the first resistor 丨, the NM 〇s transistor q2 will be turned off due to the decrease of the cathode potential of the diode D, and the NM〇s transistor will change its drain according to the operating voltage Vcc. To a low level. In addition, the charging and discharging unit 251 charges or discharges according to whether the control signal s received by the input terminal 221b is normal or abnormal, and the switch unit 252 correspondingly generates a level signal or a low level signal to the main control unit 210. Input 211. Thereby, the detecting unit 25 can perform the above-described protection function by the operation of the charging and discharging unit 251 and the switching unit 252. Preferably, the detecting circuit is configured to correspond to the number of input terminals 221b of the second full bridge converting unit 220b to respectively form respective input terminals. Of course, the 'first-to-bridge conversion unit recommends that the circuit 250 be turned off. Furthermore, although the first embodiment is based on the architecture of a dual drive converter 13

200818987W3198PA • Note, but depending on the actual design of the multi-lamp drive circuit, the detection circuit 250 can also be combined with the main control unit 210 and any full-bridge conversion unit as a full-bridge protection circuit for the designer to operate, for example. A multi-lamp drive circuit for a single-drive inverter architecture. SECOND EMBODIMENT Referring to Figure 4, there is shown a schematic diagram of a full bridge protection circuit in accordance with a second embodiment of the present invention. The difference from the first embodiment is that the detection circuit 450 of the full bridge and protection circuit 400 is coupled to the driving signal Sd generated by the full bridge conversion unit 420 to detect whether it is abnormal. As shown in FIG. 4, the full bridge conversion unit 420 includes four transistors; in the second embodiment, the PMOS transistor q1 and the NMOS transistor q2 are connected in series, and the PMOS transistor q3 and the NMOS transistor are connected in series. Q4 for example. The control signals S1~S4 of the main control unit 410 are respectively output to the gates of the four transistors ql~ to control the four transistors ql~q4 to alternately turn on and off alternately, and the two series points T1 and T2 are generated to rise via the transformer. Press and supply C to the AC drive signal Sd of the lamp. However, once any of the control signals S1 to S4 is abnormal, the drive signal Sd is also followed by an abnormality. Please refer to FIG. 5, which is a circuit diagram of the detecting circuit 450 of FIG. Compared with the third figure, the circuit structure of the charging and discharging unit 451 and the switching unit 452 of the detecting unit 450 is also different because the detected signal levels are different. In the second embodiment. The charge and discharge unit 451 includes a first diode dl, a first resistor rl, a first capacitor c1, a second capacitor c2, a second resistor r2, and a second diode d2. The first resistor rl and the first capacitor cl are and 200818987

One..." W3198PA • Connected between the ground GND and the cathode of the first diode dl. The second capacitor _ is connected between the anode of the first diode dl and the first end of the second resistor Γ2. The second end of the second resistor r2 is connected to the series point τ 1 of Fig. 4 to receive the driving signal Sd. In other embodiments, the second end of the second resistor Γ2 can also be coupled to the series point Τ2. The cathode and the anode of the second diode d2 are respectively coupled to the anode of the first diode dl and the ground GND. The switch unit 452 includes a third diode d3, and the cathode and the anode of the third diode d3 are respectively coupled to the cathode of the first diode dl and the input terminal C411 of the main control unit 410. When 420 generates the normal AC drive signal Sd, the current charges the first capacitor c1 via the second resistor r2, the second capacitor C2, and the first and second diodes d1 and d2. That is, the cathode potential of the first diode dl rises to a fixed level and is higher than the anode potential of the third diode d3 to make the third diode d3 non-conductive. However, when the driving signal Sd is abnormal, such as the signal gap or the fixed high (low) level, the second capacitor c2 will short-circuit or isolate the DC signal of the fixed level. At this time, the first capacitor c1 is discharged by the first resistor rl, and causes the cathode potential of the third diode d3 to be lowered to be turned on. As a result, the anode potential of the third diode d3 after the turn-on will be lowered. In this way, the charging and discharging unit 451 can charge or discharge according to the received normal or abnormal driving signal Sd, and the switching unit 452 can correspondingly change the potential of the input terminal 411 of the main control unit 410, and the first implementation. The example causes the main control unit 410 to stop the operation. However, it will be apparent to those of ordinary skill in the art to which the present invention pertains, in the above two embodiments.

The two detection circuits of the W3198PA 200818987 can be connected to the HTS with a known feedback circuit to the 2-bridge to the full-bridge conversion unit. They can also be used to receive the feedback power. For example, the input of the main control unit. The end can be protected by changing the feedback signal to the == pin's fine path.吏The main control is stopped according to the operation, and the road is reached. The full bridge protection circuit and the application of the above-mentioned singularity disclosed in the above-mentioned example are used. Mainly utilize the ^ ς in the full bridge protection circuit: Second, the control signal or the unit received by the unit will not follow the abnormality or damage. τ ′, 〜, 。, 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 Any technique that lies in the art, without departing from the spirit and scope of the present invention, can be used as the scope of protection of the invention::::= The scope of protection of the invention is attached. Please = 16 200818987_ρα —j/yu - rr ^ x vux r\. ' [Simple description of the drawing] Fig. 1 is a schematic view showing a conventional multi-lamp driving circuit. Fig. 2 is a schematic view showing a multi-lamp driving circuit according to the first embodiment of the present invention. Figure 3 is a circuit diagram of the detection circuit 250 of Figure 2. Figure 4 is a schematic diagram of a full bridge protection circuit in accordance with a second embodiment of the present invention. f ' Figure 5 4 circuit diagram of the debt measurement circuit 450. 17 20081 8987W3198pa ' [Main component symbol description] 100, 200: multi-lamp driving circuit 110, 210, 410: main control unit 120a, 220a: first full bridge conversion unit 120b, 220b: second full conversion unit 130, 230: first transformer 140, 240: second transformer 150, 160: feedback circuit f 250, 450: detection circuit 400: full bridge protection circuit 420 · · full bridge conversion unit R1 ~R3, rl, r2: resistance Cl, C2, cl, c2: capacitor Q1 ~ Q3, q2, q4: NMOS Body ql, q3: PMOS transistor D, dl~d3: Diode C L: Lamp Μ: a main circuit board S: sub-circuit board 18

Claims (1)

200818987 Reward PA 10. Patent application scope: 1. A multi-lamp driving circuit for driving a plurality of lamps, the multi-lamp driving circuit comprises: a main control unit having an input end and an output end, the main The output end of the control unit is configured to output a control signal; a first full bridge conversion unit, the input end of the first full bridge conversion unit is connected to the output end of the main control unit to receive the control signal; a first transformer, the primary side of the first transformer is coupled to one of the output ends of the first all-f bridge switching unit, and the secondary side of the first transformer is coupled to one of the lamps of the one of the lamps; a full-bridge conversion unit, wherein an input end of the second full-bridge conversion unit is coupled to the output end of the main control unit to receive the control signal; and a second transformer, the primary side of the second transformer is coupled to the first An output end of the second full-bridge conversion unit, the second side of the second transformer is coupled to the other end of the lamp; and a detecting circuit coupled to the input of the first or second full-bridge conversion unit End and coupling the main The detecting circuit changes the control unit when the detecting circuit detects that the control signal received by the input end of the first or second full-bridge converting unit is abnormal, and the detecting circuit detects the abnormality of the control signal received by the input end of the first or second full-bridge converting unit The potential of the input terminal causes the main control unit to stop outputting the control signal. 2. The multi-lamp driving circuit of claim 1, wherein the detecting circuit detects that the control signal received by the input end of the second full-bridge converting unit is normal, a high-level signal to the input end of the main control unit of the 20081 8987W3198pa, when the detecting circuit detects that the control signal received by the input end of the second full-bridge conversion unit 7G is abnormal, The low level signal is sent to the input of the main control unit. A multi-lamp driving circuit as described in claim 2, wherein the detecting circuit comprises: a — a charging and discharging unit coupled to the input end of the first or second full bridge converting unit Receiving the control signal, when the control signal is normal, the charging and discharging unit is charged according to the control signal; and a switching unit is coupled to the charging and discharging unit and the input end of the main control unit, when When the control signal is abnormal, the charging and discharging unit performs discharging: causing the switching unit to generate the low level signal. 4. The multi-lamp driving circuit according to claim 3, wherein the charging and discharging unit comprises: an octapole body; a first-resistor and a --capacitor, which are connected in parallel to the grounding terminal and the a second capacitor is coupled between the anode of the diode and the first end of the second resistor, the second one The second end is coupled to an operating voltage; and the source and the drain are respectively respectively terminated by a transistor, and one of the gates of the transistor is coupled to the input end of the first or second full bridge converting unit, the transistor A multi-lamp driving circuit as described in claim 4, wherein the switching unit comprises: a first transistor 'the first one' One of the gate and the source of the crystal are respectively connected to the anode and the ground of the diode; a second transistor, one of the gate and the source of the second transistor respectively The transistor and the pole and the grounding end of the second transistor are coupled to the pole The input terminal of the control unit; and a resistor coupled to an operating voltage between the gate and said second transistor has. 6. A full bridge protection circuit, the full bridge protection circuit is applicable to a multi-lamp driving circuit, the full bridge protection circuit comprises: a main control unit having an input end and an output end, the main control unit The output terminal is configured to output a control signal; a full bridge conversion unit, wherein an input end of the full bridge conversion unit is coupled to the output end of the main control unit to receive the control signal; and a detection circuit coupled to the The input end of the full bridge conversion unit and the input end of the main control unit, when the detection circuit detects that the control signal received by the input end of the full bridge conversion unit is abnormal, the detection circuit changes The potential of the input terminal of the main control unit causes the main control unit to stop outputting the control signal. 7. The full bridge protection circuit according to claim 6 of the patent application, wherein 21 200818987W3198PA generates a high when the detection circuit receives the control signal from the input end of the full bridge conversion unit. The level signal is sent to the input end of the main control unit, and when the detecting circuit detects that the input of the full bridge conversion unit is abnormal, the control signal is abnormal, and a low level signal is generated to the main control The input of the early yuan. 8. The multi-lamp driving circuit of claim 7, wherein the detecting circuit comprises: a charging and discharging unit coupled to the input end of the full-bridge converting unit to receive the control signal, when _ When the track number is normal, the button unit is charged according to the control number; and * a switch unit coupled to the charge and discharge unit and the input end of the main control unit. When the control signal is abnormal, the charge and discharge unit performs Discharging, causing the switching unit to generate the low level signal. 9. The multi-lamp drive according to claim 8 of the patent application scope, wherein the charge and discharge unit comprises: a " a diode; is connected in parallel to a ground and the first resistor and a first capacitor, Between one of the cathodes; a second capacitor and a second resistor', one of the second capacitors and one of the second resistors, the first end of the second resistor is coupled to the operating voltage; - the transistor - the transistor - the gate is lightly connected to the input end of the full bridge conversion unit 22 200818987w3i9SPA, one of the source and the one of the transistor is coupled to the ground and the first The first end of the two resistors. 10. The multi-lamp driving circuit of claim 9, wherein the switching unit comprises: a first transistor, wherein a gate and a source of the first transistor are respectively coupled to the diode a cathode and a grounding end; a second transistor, a gate and a source of the second transistor are respectively coupled to the drain of the first transistor and the ground, the second transistor a drain is coupled to the input end of the main control unit; and a resistor is coupled between an operating voltage and the gate of the second transistor. 11. A full bridge protection circuit, the full bridge protection circuit is applicable to a multi-lamp driving circuit, the full bridge protection circuit comprises: a main control unit having an input end; a full bridge conversion unit coupled to the main control The unit includes a first transistor, a second transistor, a third transistor, and a fourth transistor. The first and second transistors are connected in series, and the third and fourth transistors are connected in series. The control unit controls the first to fourth transistors to generate a driving signal; and a detecting circuit coupled to the driving signal and the input end of the main control unit, when the detecting circuit detects that the driving signal is abnormal The detecting circuit changes the potential of the input end of the main control unit, so that the main control unit stops controlling the first to fourth transistors to generate the driving signal. 23 200818987w319spj 12. The full-bridge protection circuit according to claim 11, wherein when the detection and I-channel detect that the driving signal is normal, the _ high-level signal is generated to the main control unit. At the input end, when the side circuit detects that the driving signal is abnormal, the system generates a scale-down to the main control unit: 3⁄43⁄4 〇 13. The full bridge protection circuit according to claim 12, wherein the detection circuit comprises: - a charge and discharge unit connected to the series of the first and second transistors to receive the drive signal 'When the When the driving signal is normal, the charging and discharging unit performs charging according to the driving signal; and the unit and the charging and discharging unit of the main control unit discharge, so that a switching unit is coupled to the charging and discharging end, when the driving signal is abnormal. The switch unit generates the low level signal. The middle is called (4) the editing circuit, a first diode; the first-resistor and the first capacitor are connected in parallel between the cathode of the diode and the second cathode; a second resistor, between the anode of the first two (four) and the first end of the second resistor, wherein the second end of the second resistor is connected to the series of the first and second transistors And a second diode, a cathode of the second diode and an anode coupled to the anode and the ground of the first diode, respectively. The full-bridge protection circuit of claim 14, wherein the switch unit further comprises: a diode, one of the diodes is coupled to the cathode of the first diode, and the second One of the poles is coupled to the input of the main control unit. / 16. A multi-lamp driving circuit for driving a plurality of lamps, the multi-lamp driving circuit comprises: a main control unit having an input; a full-bridge conversion unit coupled to the main control unit, And including a first transistor, a second transistor, a third transistor and a fourth transistor, the first and second transistors are connected in series, and the third and fourth transistors are connected in series, the main control unit Controlling the first to fourth transistors to generate a driving signal; and a transformer, the primary side of the transformer is coupled to the full-bridge conversion unit to receive the driving signal by C, and the secondary side of the transformer is coupled to the lamps One of the light pipes; and a detecting circuit coupled to the driving signal and the input end of the main control unit, when the detecting circuit detects that the driving signal is abnormal, the detecting circuit changes the main control The potential of the input terminal of the unit causes the main control unit to stop controlling the first to fourth transistors to generate the driving signal. 17. Multi-lamp driving power as described in claim 16 of the patent application 25 20081 8987w3198pa Road - When the detection signal detects that the driving signal is normal, it generates a level signal to the diagnosis ±4*. Mouth — the source of the yuan. 'The system produces - the fresh number to the main control list · % humiliation range mentioned in item 17, /, the detection circuit includes: a charge and discharge single open. ^ C receive the drive (four) 'round the first - and the second transistor is connected in series according to the driving signal ί行=Drive = No. 'The charging and discharging unit root switching unit' is coupled to the charging and discharging unit and the main control unit of the input: When the signal is abnormal 'The charge and discharge unit performs discharge so that the Μ switch generates the low level signal 7L early. 19. The multi-lamp driving circuit of claim 18, wherein the charging and discharging unit further comprises: a first diode; - a first-resistor and a --capacitor' are connected in parallel to the ground And a second capacitor and a second resistor, the second capacitor is coupled to the first diode, the anode and the second resistor - the first end a second end of the second resistor is coupled to the series of the first and second transistors; and a second diode 'the cathode of the second diode and an anode are respectively coupled to the first The anode of the diode and the ground. The method of claim 19, wherein the switch unit further comprises a diode, the cathode of the diode is coupled to the first diode The cathode 'the anode of the diode minus the input of the main control unit. 21. A multi-lamp driving circuit for driving a plurality of lamps, the multi-lamp driving circuit comprises: · a main control unit 'having an input end and an output end, and the output end of the main control unit is used a full-bridge conversion unit, an input end of the full-bridge conversion unit is coupled to the output end of the main control unit to receive the control signal; a transformer 'the primary side of the transformer is coupled to the whole An output end of the bridge conversion unit is coupled to one end of one of the lamps; and a debt measuring circuit, the input terminal of the full bridge conversion unit and the main control unit At the input end, when the detecting circuit detects that the control signal received by the input end of the full bridge converting unit is abnormal, the detecting circuit changes the potential of the input end of the main control unit, so that the The main control unit stops outputting the control signal accordingly. The multi-lamp driving circuit of claim 21, wherein when the detecting circuit detects that the control signal received by the input end of the full-bridge converting unit is normal, the system generates a high-precision a bit signal to the main 27 20081 8987^3198ρα , the input end of the control unit, when the detecting circuit detects that the control signal received by the input end of the full bridge conversion unit is abnormal, a low level signal is generated. To the input of the main control unit. The multi-lamp driving circuit of claim 22, wherein the detecting circuit comprises: a charging and discharging unit coupled to the input end of the full-bridge converting unit to receive the control signal, when the control When the signal is normal, the charging and discharging unit is charged according to the control signal; and the switch unit 7G is coupled to the charging and discharging unit and the input end of the main control unit. When the control signal is abnormal, the charging and discharging unit Discharge is performed to cause the switching unit to generate the low level signal. 24. The multi-lamp driving circuit of claim 23, wherein the charging and discharging unit comprises: a diode; a first resistor and a first capacitor connected in parallel to a ground and the second a second capacitor and a second resistor coupled between the % pole of one of the diodes and the first end of the first resistor, the second resistor a second end is coupled to an operating voltage; and a transistor, one of the gates of the transistor is coupled to the input end of the full bridge conversion unit, and one source and one of the transistors are respectively connected to the ground And the first end of the second resistor. The multi-lamp driving circuit of claim 24, wherein the switching unit comprises: a first transistor, a gate of the first transistor and a source coupled respectively Connecting the cathode of the diode and a grounding end; a second transistor, a gate and a source of the second transistor are respectively coupled to the drain of the first transistor and the ground end, One of the second transistor is coupled to the input end of the main control unit; and a resistor is coupled between an operating voltage and the gate of the second transistor. 29