CN1677827A - Push-upll control signal generating circuit and method thereof - Google Patents
Push-upll control signal generating circuit and method thereof Download PDFInfo
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- CN1677827A CN1677827A CN 200410029916 CN200410029916A CN1677827A CN 1677827 A CN1677827 A CN 1677827A CN 200410029916 CN200410029916 CN 200410029916 CN 200410029916 A CN200410029916 A CN 200410029916A CN 1677827 A CN1677827 A CN 1677827A
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Abstract
The disclosed circuit outputs two control signals in use for direct controlling and driving operation of diverter switch in push-pull type circuit architecture. The circuit comprises following parts: waveform generator, first AND unit, second AND unit, clock generator connected to waveform generator and first AND unit, and through NOT gate connected to second AND unit, soft starting up unit connected to clock generator, sample hold unit through error amplifier connected to feedback circuit, first and second comparators connected to corresponding parts, and static time control unit connected to waveform generator, first and second AND gate units.
Description
Technical field
The present invention relates to a kind of push-pull type control signal generation circuit and method thereof, relate in particular to and a kind ofly can export control signal, and the action of diverter switch that can direct controlling and driving push-pull circuit framework, and then reach the signal generating circuit and the method thereof of the conversion and the transmission of electric power.
Background technology
In increasingly sophisticated electronics, the computer installation, supply unit is more important, supply unit can be divided into linear mode (linear type) and exchanged form (switching type) two big classes, because its shortcoming of linear mode (linear type) is more, therefore, the supply unit of industrial circle production at present all uses exchanged form (switching type) to reach.
The converter circuit (Inverter Circuit) that the supply of electric power of TFT panel backlight (Power Supply) mainly is to use direct current DC to be converted into alternating current AC is reached the conversion of energy and is driven the luminous of cold cathode fluorescent lamp pipe (CCFL).Existing converter circuit (Inverter Circuit) is because of the difference of circuit topography, and have general the branch such as semi bridge type inversion circuit, full-bridge current circuit and push-pull type converter circuit etc., is the converter circuit that direct current DC is converted to alternating current AC.
Please refer to Fig. 1, drive the circuit diagram of load for existing push-pull type converter circuit.Transformer T1 is divided into the front stage circuits 101 of primary side and the late-class circuit 102 of secondary side with circuit region.This front stage circuits 101 includes: a direct current power Vcc, one first switch Q1, a second switch Q2 etc., this late-class circuit 102 includes: a load (Load) etc.Cooperate Fig. 2, be existing push-pull type control signal and load end output waveform schematic diagram.The first control signal a and the second control signal b are sent to control end A, the B of the first switch Q1 and second switch Q2 respectively, simultaneously, control first switch Q1 of front stage circuits 101 and the change action of second switch Q2 respectively.Change action is that the first switch Q1 and second switch Q2 stagger a bit of time a little, and alternately (alternately) is done the ON/OFF action.The DC power supply Vcc of front stage circuits 101 is in order to energy to be provided and by transformer T1 the boost in voltage of DC power supply Vcc to be transformed into late-class circuit 102, in order to drive load (Load).The secondary side output voltage waveforms c of transformer T1 is an alternating voltage waveform, and as shown in Figure 2, secondary side output voltage waveforms c is an alternating voltage waveform.
Continuation is with reference to figure 1, because its operating principle of push-pull type converter circuit is that the first switch Q1 and second switch Q2 stagger a bit of time a little, and alternately (alternately) does ON/OFF action, therefore control signal a, b as shown in Figure 2 need a bit of when quiet the time (dead time) cause burning of transformer T1 in order to avoid the first switch Q1 and second switch Q2 conducting simultaneously.And control signal a, b need the electricity needs according to load (Load) end, and then control break first switch Q1 and second switch Q2 ground change action, in order to provide load (Load) required electric power.Moreover; control signal a, b need the various situations of a kind of load (Load) end and the working temperature situation that the present invention produces circuit; situations such as for example output voltage is low excessively, output voltage is too high, fluorescent tube open circuit or temperature overheating; and then stop the change action of the first switch Q1 and second switch Q2, to reach the function of circuit protection.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of push-pull type control signal generation circuit and method thereof, two control signals can be provided, and control the change action of two electronic switches of push-pull type converter circuit respectively, make DC power supply be converted into AC power, and provide electric power to use to load by transformer.
To achieve these goals, the invention provides a kind of push-pull type control signal generation circuit and method thereof, it is a side that is connected to a transformer by two electronic switches, in order to controlling the keying of two electronic switches, and a direct current power supply is switched to the side that an AC power is sent to transformer.Simultaneously, the leakage inductance and the electric capacity (C1, C2, C5) that utilize transformer to produce form resonant network, in order to produce a string ripple to provide the load action required electric power.Moreover, utilize the load condition of feedback circuit acquisition transformer secondary side, and after the processing by a kind of push-pull type control signal generation circuit of the present invention, export and produce control signal, to reach the electric power adjustment and the protection of load end.
Above-mentioned a kind of push-pull type control signal generation circuit provided by the invention, its characteristics are, are connected to a side of a transformer by two electronic switches, in order to control the keying of two electronic switches, with a direct current power source conversion is an AC power, uses so that a load to be provided, and includes:
One first with the gate logic unit, in order to the logical operation of doing to amass, and export one first control signal;
One second with the gate logic unit, in order to the logical operation of doing to amass, and export one second control signal;
One circuit protection unit, be connected in this first with gate logic unit and second and the gate logic unit, and be connected to the secondary side of this transformer, in order to receive a feedback signal by a feedback circuit;
One waveform generator is in order to produce a sawtooth waveform signal;
One clock generator is connected in this waveform generator and this first and gate logic unit, and by a not gate be connected to this second with the gate logic unit, according to this sawtooth waveform signal in order to produce a clock signal;
One soft start-up unit is connected in this clock generator, receives this clock signal, and exports a starting-up signal and a count signal, in order to carry out boot action;
One sampling keeping unit is connected to this feedback circuit by an error amplifier, obtains a voltage feedback signal, and exports a Voltage Feedback inhibit signal;
One first comparator is connected in this soft start-up unit and this waveform generator, and relatively this sawtooth waveform signal and this count signal are exported one first comparison signal;
One or the gate logic unit, be connected in this soft start-up unit, this first comparator, this first with gate logic unit and this second and gate logic unit, with this starting-up signal and this first comparison signal work or logical operation;
One second comparator, be connected in this sampling keeping unit, this waveform generator, this first with gate logic unit and this second and gate logic unit, relatively this sawtooth waveform signal and this Voltage Feedback inhibit signal are exported one second comparison signal; And
One control unit when quiet, be connected in this waveform generator, this first and lock logical block and this second and gate logic unit, receive this sawtooth waveform signal, export one and adjust signal when quiet.
Above-mentioned push-pull type control signal generation circuit, its characteristics are, also include a constant-current source and are connected to this error amplifier by a switching switch, and a fixing electric current is provided.
Above-mentioned push-pull type control signal generation circuit, its characteristics are, also include a voltage-adjusting unit and are connected in this DC power supply, and provide circuit working required electric power.
Above-mentioned push-pull type control signal generation circuit, its characteristics are that this soft start-up unit includes:
One counter is in order to the counting available machine time; And
One digital/analog converter is exported the available machine time with analog form.
Above-mentioned push-pull type control signal generation circuit, its characteristics are that this circuit protection unit includes:
One under-voltage protection circuit is according to the under-voltage protection of this feedback signal as circuit;
One temperature protection circuit is according to the overtemperature protection of this feedback signal as circuit;
One excess voltage protection is according to the overvoltage protection of this feedback signal as circuit; And
One fluorescent tube open loop protection circuit is according to the protection of this feedback signal as load open circuit.
Above-mentioned push-pull type control signal generation circuit, its characteristics are that this excess voltage protection is controlled the keying of this diverter switch.
Above-mentioned push-pull type control signal generation circuit, its characteristics are that this load is a cold cathode fluorescent lamp pipe.
Simultaneously; the present invention can utilize a power protection unit; obtain the various situations of transformer secondary lateral load (Load) end and the working temperature situation that the present invention produces circuit by feedback circuit; situations such as for example output voltage is low excessively, output voltage is too high, fluorescent tube open circuit or temperature overheating; and then stop the change action of two electronic switches, to reach the function of circuit protection.
Moreover the present invention utilizes control unit when quiet to obtain fixing time (dead time) when quiet, causes transformer short-circuit to burn in order to avoid the conducting simultaneously of two electronic switches.And the present invention can be according to the electricity needs of load (Load) end, and then the change action of control break two electronic switches, in order to provide load (Load) required electric power.Simultaneously, the switching that the present invention utilizes a soft start-up unit to carry out two electronic switches activates, excessive burst current and voltage when activating in order to reduce, and cause burning of two electronic switches, and the life-span of prolonging lamp tube.
The voltage feedback signal that the present invention more holds in order to reception load (Load) by a sampling keeping unit, and in the maintenance action of each cycle clock signal execution voltage feedback signal, and then improve the energy imbalance that has the signal that exports load to now.
At above-mentioned signal generating circuit, the present invention also provides a kind of push-pull type control signal production method, includes:
Produce a sawtooth waveform signal, obtain by a waveform generator;
Produce a clock signal, obtain according to this sawtooth waveform signal by a clock generator;
Produce a reverse clock signal, obtain through a not gate by this clock signal;
Produce one and adjust signal when quiet, control unit obtains according to this sawtooth waveform signal when quiet by one;
Sampling also keeps a voltage feedback signal, is connected to a feedback circuit by a sampling keeping unit by an error amplifier and obtains;
Relatively this voltage feedback signal and this sawtooth waveform signal are carried out by one second comparator, and are exported one second comparison signal;
Count this clock signal, and export a count signal and a starting-up signal, carry out by a soft start-up unit;
Relatively this count signal and this sawtooth waveform signal are carried out by one first comparator, and are exported one first comparison signal;
Produce one or gate signal, by this starting-up signal and the execution of this first comparison signal or logical operation;
Produce one first control signal, adjust signal, this second comparison signal, this clock signal and this or gate signal by this when quiet and carry out long-pending logical operation; And
Produce one second control signal, adjust signal, this second comparison signal, this reverse clock signal and this or gate signal by this when quiet and carry out long-pending logical operation.
Describe the present invention below in conjunction with the drawings and specific embodiments, but not as a limitation of the invention.
Description of drawings
Fig. 1 drives the circuit diagram of load for existing push-pull type converter circuit;
Fig. 2 is existing push-pull type control chip output control signal and load end output voltage waveforms formula schematic diagram;
Fig. 3 drives the circuit diagram of load for push-pull type control signal generation circuit of the present invention;
Fig. 4 is the circuit diagram of push-pull type control signal generation circuit of the present invention;
Fig. 5 is the internal signal waveforms schematic diagram of push-pull type control signal generation circuit of the present invention.
Description of reference numerals
The 101-front stage circuits
The 102-late-class circuit
The T1-transformer
1-push-pull type control signal generation circuit
The 2-feedback circuit
The 4-power-supply unit
The 5-load
The soft start-up unit of 102-
Control unit when 104-is quiet
The 106-clock generator
The 108-sampling keeping unit
The 110-waveform generator
112-first and gate logic unit
114-second and gate logic unit
116-first comparator
118-second comparator
120-or gate logic unit
The 122-not gate
The 124-circuit protection unit
The 126-error amplifier
The 128-constant current
The 130-voltage-adjusting unit
DRV1-first output
DRV2-second output
The FB-pressure feedback port
The CLAMP-sense terminal
Embodiment
Please refer to Fig. 3, drive the circuit diagram of load for push-pull type control signal generation circuit of the present invention.Wherein push-pull type control signal generation circuit 1 is connected to the side of a transformer T1 by two electronic switch Q3, Q4, in order to control the keying of two electronic switch Q3, Q4.Push-pull type control signal generation circuit 1 also is connected to the secondary side of transformer T1 by a feedback circuit 2, in order to obtain a feedback signal of load 5.Be connected in a power-supply unit 4 simultaneously in order to obtain a working power Vdd (not indicating).Push-pull type control signal generation circuit 1 is exported two control signals by the first output DRV1 and the second output DRV2, and control the keying of two electronic switch Q3, Q4 respectively, be used for the direct current power supply DC that power-supply unit 4 provides is converted into an AC power AC, use so that load to be provided.In the above-mentioned explanation, this load is a cold cathode fluorescent lamp pipe (CCFL).
Cooperate Fig. 3, please refer to Fig. 4, be the circuit diagram of push-pull type control signal generation circuit of the present invention.Push-pull type control signal generation circuit 1 of the present invention, be connected to the control end of electronic switch Q3 by one first output DRV1, be connected to the control end of electronic switch Q4 by one second output DRV2, an one pressure feedback port FB and a sense terminal CLAMP are connected to feedback circuit 2 simultaneously, include: one first with gate logic unit 112, in order to the logical operation of doing to amass; One second with gate logic unit 114, in order to the logical operation of doing to amass; One circuit protection unit 124, be connected in this first with gate logic unit 112 and second and gate logic unit 114, utilize sense terminal CLAMP to be connected to the feedback circuit 2 of Fig. 3, and be connected to the secondary side of this transformer T1 by feedback circuit 2; One waveform generator 110; One clock generator 106, be connected in this waveform generator 110 with this first with gate logic unit 112, and by a not gate 122 be connected to this second with gate logic unit 114; One soft start-up unit 102 is connected in this clock generator 106, in order to carry out boot action; One sampling keeping unit 108 is connected to this feedback circuit 2 via pressure feedback port FB again by an error amplifier 126; One first comparator 116 is connected in this soft start-up unit 102 and this waveform generator 110; One or gate logic unit 120, be connected in this soft start-up unit 102, this first comparator 116, this first with gate logic unit 112 and this second and gate logic unit 114, carry out or logical operation (OR); One second comparator 118, be connected in this sampling keeping unit 108, this waveform generator 110, this first with gate logic unit 112 and this second and gate logic unit 114; And a control unit 104 when quiet, be connected in this waveform generator 110, this first with gate logic unit 112 and this second and gate logic unit 114.
In the above-mentioned explanation, push-pull type control signal generation circuit 1 of the present invention also includes a constant-current source 128, switches switch SW by one and is connected to this error amplifier 126, in order to a fixing electric current to be provided.Simultaneously, also include a voltage-adjusting unit 130, be connected in power-supply unit 4, obtain a direct current power supply, in order to provide 1 work of push-pull type control signal generation circuit required electric power VCC by a working power end VDD.
In the above-mentioned explanation, the circuit protection unit 124 of push-pull type control signal generation circuit 1 of the present invention includes: a under-voltage protection circuit, a temperature protection circuit, an excess voltage protection and a fluorescent tube open loop protection circuit etc.Simultaneously, the soft start-up unit 102 of push-pull type control signal generation circuit 1 of the present invention includes: a counter and a digital/analog converter.
Please refer to Fig. 5, be the internal signal waveforms schematic diagram of push-pull type control signal generation circuit of the present invention.Wherein transverse axis is time (t) axle, and the longitudinal axis is voltage (V) axle.As shown in Figure 5, the internal signal waveforms of push-pull type control signal generation circuit of the present invention includes: a voltage feedback signal a, a Voltage Feedback inhibit signal b, a sawtooth waveform signal c, one adjust signal d, one second comparison signal e, a count signal f, one or gate signal g, a clock signal h, one first control signal i, one second control signal j, a starting-up signal k and one first comparison signal m when quiet.
Cooperate Fig. 5, please refer to Fig. 4, push-pull type control signal generation circuit 1 of the present invention utilizes sampling keeping unit 108 by error amplifier 126, is connected to feedback circuit shown in Figure 32 via pressure feedback port FB again, and then obtains feedback signal.This feedback signal is voltage feedback signal a.Sampling keeping unit 108 keeps operating stably with voltage feedback signal a, makes it no longer to float, and output voltage feedback inhibit signal b is to second comparator 118 simultaneously.Sampling keeping unit 108 is the clock signal h according to each cycle, in order to carrying out the maintenance operating stably of voltage feedback signal a, and then output voltage feedback inhibit signal b.Waveform generator 110 output sawtooth waveform signal c, and be sent to clock generator 106, make clock generator 106 export clocking h.Sawtooth waveform signal c is sent to control unit 104 when quiet simultaneously, makes when quiet control unit 104 outputs produce and adjusts clock d when quiet.Sawtooth waveform signal c also is sent to second comparator, 118, the second comparators 118 relatively sawtooth waveform signal c and Voltage Feedback inhibit signal b simultaneously, and then export the second comparison signal e.
Continue to cooperate Fig. 5, please refer to Fig. 4, the soft start-up unit 102 receive clock signal h of push-pull type control signal generation circuit 1 of the present invention, and utilize inner counter according to clock signal h, in order to count the default circuit available machine time.Digital signal behind the counting is handled via the digital/analog converter of soft start-up unit 102 inside, makes digital signal be converted into analog signal output, and this analog signal is count signal f.Simultaneously, when the soft 102 default circuit available machine times of start-up unit arrived, the starting-up signal k of soft start-up unit 102 outputs changed into high potential by electronegative potential.
Continue to cooperate Fig. 5, please refer to Fig. 4, first comparator 116 of push-pull type control signal generation circuit 1 of the present invention receives and relatively this sawtooth waveform signal c and count signal f, and then exports the first comparison signal m and be sent to or gate logic unit 120.Or gate logic unit 120 receives the starting-up signal k and the first comparison signal m simultaneously, and output or gate signal g.
Continue to cooperate Fig. 5; please refer to Fig. 4; first of push-pull type control signal generation circuit 1 of the present invention is adjusted the guard signal that signal d and circuit protection unit 124 transmit with gate logic unit 112 receive clock signal h or gate signal g, the second comparison signal e, when quiet; and with the logical operation of it work long-pending (AND), in order to export the first control signal i.Simultaneously, second receives with gate logic unit 114 or gate signal g, the second comparison signal e, adjusts the guard signal that signal d and circuit protection unit 124 transmit when quiet, and by not gate 122 receive clock signal h.Second does the logical operation of long-pending (AND) with gate logic unit 114 with the signal of above-mentioned reception, in order to export the second control signal j.
Cooperate Fig. 4, please refer to Fig. 5, when time t0-t1, sawtooth waveform signal c respectively when quiet control unit 104 adjust signal d and clock signal h when quiet with clock generator 106 outputs, the time is td when adjusting signal d quiet when quiet, and at this moment, clock signal h is a high potential.Because Voltage Feedback inhibit signal b is greater than sawtooth waveform signal c, the second comparison signal e of second comparator, 118 outputs is a high potential.And sawtooth waveform signal c is greater than count signal f, so the first comparison signal m of first comparator, 116 outputs is an electronegative potential.Simultaneously, because default available machine time no show still, so starting-up signal k is an electronegative potential.Because the starting-up signal k and the first comparison signal m are all electronegative potential, thus gate logic unit 120 output or gate signal g be electronegative potential.Therefore, when time t0-t1, first exerts the first control signal i and the second control signal j that 112 and second AND 114 exports and is all electronegative potential with gate logic is flirtatious.
Cooperate Fig. 4, please refer to Fig. 5, in time t1-t2, at this moment, clock signal h is an electronegative potential, and to adjust signal d when quiet be electronegative potential.Identical when the control signal of circuit output and time t0-t1, promptly the first control signal i and the second control signal j that export of first AND 112 and second AND 114 is all electronegative potential.
Cooperate Fig. 4, see also Fig. 5, in time t2-t3, clock signal h still be an electronegative potential, and adjustment signal d is a high potential when quiet.Because Voltage Feedback inhibit signal b is still greater than sawtooth waveform signal c, so the second comparison signal e is a high potential.And sawtooth waveform signal c is less than count signal f, so the first comparison signal m of first comparator, 116 outputs is a high potential.Simultaneously, because default available machine time no show still, so starting-up signal k is an electronegative potential.Because the starting-up signal k and the first comparison signal m are all high potential, thus gate logic unit 120 output or gate signal g be high potential.Therefore, when time t2-t3, the first control signal i of first AND, 112 outputs still is an electronegative potential, and the second control signal j of second AND, 114 outputs is a high potential.
Cooperate Fig. 4, please refer to Fig. 5, identical when the control signal of circuit output this moment and time t0-t1 in time t3-t4, promptly the first control signal i and the second control signal j that export of first AND 112 and second AND 114 is all electronegative potential.
Cooperate Fig. 4, please refer to Fig. 5, in time t4-t5, this moment, clock signal h was a high potential, and to adjust signal d when quiet be high potential.Because Voltage Feedback inhibit signal b is greater than sawtooth waveform signal c, the second comparison signal e of second comparator, 118 outputs is a high potential.And sawtooth waveform signal c is less than count signal f, so the first comparison signal m of first comparator, 116 outputs is a high potential.Simultaneously, because default available machine time no show still, so starting-up signal k is an electronegative potential.Because the first comparison signal m is a high potential, thus gate logic unit 120 output or gate signal g be high potential.Therefore, when time t4-t5, the first control signal i of first AND, 112 outputs is a high potential, and the second control signal j of second AND, 114 outputs is an electronegative potential.
Cooperate Fig. 4, please refer to Fig. 5, identical when the control signal of circuit output this moment and time t0-t1 in time t5-t6, promptly the first control signal i and the second control signal j that export of first AND 112 and second AND 114 is all electronegative potential.
Cooperate Fig. 4, please refer to Fig. 5, in time t6-t7, clock signal h is an electronegative potential, and to adjust signal d when quiet be high potential.Because Voltage Feedback inhibit signal b is greater than sawtooth waveform signal c, the second comparison signal e of second comparator, 118 outputs is a high potential.And sawtooth waveform signal c is less than count signal f, so the first comparison signal m of first comparator, 16 outputs is a high potential.Simultaneously, because default available machine time no show still, so starting-up signal k is an electronegative potential.Because the first comparison signal m is a high potential, thus gate logic unit 120 output or gate signal g be high potential.Therefore, when time t6-t7, the first control signal i of first AND, 112 outputs is an electronegative potential, and the second control signal j of second AND, 114 outputs is a high potential.
Cooperate Fig. 4, please participate in Fig. 5, identical when the control signal of circuit output this moment and time t0-t1 in time t7-t8, promptly the first control signal i and the second control signal j that export of first AND 112 and second AND 114 is all electronegative potential.
Cooperate Fig. 4, please refer to Fig. 5, time t0-t8 is the available machine time of circuit.After time t8, the first control signal i of first AND 112 and the output of second AND 114 and the second control signal j can be subjected to clock signal h, when quiet adjustment signal d and the second comparison signal e influence and change.
In the above-mentioned explanation, when time t8, circuit reaches the default available machine time, at this moment, starting-up signal k rises to high potential by electronegative potential, therefore, gate logic unit 120 output or gate signal g be high potential, so the first control signal I of circuit after start, adjusts the signal d and the second comparison signal e and does long-pending logical operation and obtain by clock signal h, when quiet.The second control signal j adjusts the signal d and the second comparison signal e and does long-pending logical operation and obtain after start by reverse clock signal h, when quiet.
Cooperate Fig. 4, please refer to Fig. 5, circuit protection unit 124 detects the working condition of load 5 by feedback circuit 2 shown in Figure 3, when brownout, overtension or the fluorescent tube of load 5 can't be lighted and when opening a way, circuit protection unit 124 can begin action.Circuit protection unit 124 includes: under-voltage protection circuit, temperature protection circuit, excess voltage protection and fluorescent tube open loop protection circuit; be to obtain a feedback signal by feedback circuit 2; and export a decapacitation signal be sent to first with gate logic unit 112 and first and gate logic unit 114; make the first control signal i and the second control signal j of circuit output be able to decapacitation, and stop action.
In the above-mentioned explanation, when load 5 overvoltage, excess voltage protection is control its switch SW action conducting (ON), makes constant-current source 128 fixing electric currents can flow into a resistance (not indicating), and then obtains a voltage also higher than reference voltage Vr.At this moment, the voltage feedback signal a of error amplifier 126 outputs drops to electronegative potential.Therefore; Voltage Feedback inhibit signal b is electronegative potential simultaneously; and the second comparison signal e of second comparator, 118 outputs is an electronegative potential; and then make win with gate logic unit 112 and first and the first control signal i and the second control signal j of gate logic unit 114 output be electronegative potential decapacitation state, and reach the overvoltage protection of load 5.
As described above, after having served as voltage failure and going out, excess voltage protection is a control its switch SW open circuit (OFF), and this moment, normal operating state was recovered by circuit system.
Next a kind of push-pull type control signal of the present invention production method is described: at first, produce a sawtooth waveform signal, obtain by a waveform generator; Then, export a clock signal,, obtain according to this sawtooth waveform signal by a clock generator; Then, produce a reverse clock signal, for this clock signal obtains through a not gate; Simultaneously, export one and adjust signal when quiet, control unit when quiet obtains according to this sawtooth waveform signal by one; Moreover, take a sample and keep a voltage feedback signal, be connected to a feedback circuit by a sampling keeping unit by an error amplifier and obtain; Then, relatively this voltage feedback signal and this sawtooth waveform signal are carried out by one second comparator, and are exported one second comparison signal; Simultaneously, count this clock signal, and export a count signal and a starting-up signal, carry out by a soft start-up unit; Then, relatively this count signal and this sawtooth waveform signal are carried out by one first comparator, and are exported one first comparison signal; Again, generation one or gate signal are by this starting-up signal and execution of this first comparison signal or logical operation (OR); At last, export one first control signal, adjust when quiet by this signal, this second comparison signal, this clock signal and should or gate signal carry out the logical operation of long-pending (AND); At last, export one second control signal, adjust when quiet by this signal, this second comparison signal, this reverse clock signal and should or gate signal carry out the logical operation of long-pending (AND).
In sum, a kind of push-pull type control signal generation circuit of the present invention and method thereof, it can provide two control signals, and controls the change action of two electronic switches of push-pull type converter circuit respectively.Simultaneously; the present invention can utilize the power protection unit; obtain the various situations of Circuit Fault on Secondary Transformer load end and the working temperature situation that the present invention produces circuit by feedback circuit; for example output voltage is low excessively; output voltage is too high; situations such as fluorescent tube open circuit or temperature overheating, and then stop the change action of two electronic switches, to reach the function of circuit protection.
Moreover the present invention utilizes control unit when quiet to obtain fixing time (dead time) when quiet, causes transformer short-circuit to burn in order to avoid the conducting simultaneously of two electronic switches.And the present invention can be according to the electricity needs of load end, and then the change action of control break two electronic switches, in order to provide load required electric power.Simultaneously, the present invention utilizes soft start-up unit to activate in order to the switching of carrying out two electronic switches, and then reduces burst current and voltage excessive when activating, and causes burning of electronic switch, and the life-span of prolonging lamp tube.
Simultaneously, the voltage feedback signal that the present invention also holds in order to reception load (Load) by sampling keeping unit, and in the maintenance action of each cycle clock signal execution voltage feedback signal, and then improve the energy imbalance that has the signal that exports load to now.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.
Claims (8)
1, a kind of push-pull type control signal generation circuit is characterized in that, is connected to a side of a transformer by two electronic switches, in order to control the keying of two electronic switches, is an AC power with a direct current power source conversion, uses so that a load to be provided, and includes:
One first with the gate logic unit, in order to the logical operation of doing to amass, and export one first control signal;
One second with the gate logic unit, in order to the logical operation of doing to amass, and export one second control signal;
One circuit protection unit, be connected in this first with gate logic unit and second and the gate logic unit, and be connected to the secondary side of this transformer, in order to receive a feedback signal by a feedback circuit;
One waveform generator is in order to produce a sawtooth waveform signal;
One clock generator is connected in this waveform generator and this first and gate logic unit, and by a not gate be connected to this second with the gate logic unit, according to this sawtooth waveform signal in order to produce a clock signal;
One soft start-up unit is connected in this clock generator, receives this clock signal, and exports a starting-up signal and a count signal, in order to carry out boot action;
One sampling keeping unit is connected to this feedback circuit by an error amplifier, obtains a voltage feedback signal, and exports a Voltage Feedback inhibit signal;
One first comparator is connected in this soft start-up unit and this waveform generator, and relatively this sawtooth waveform signal and this count signal are exported one first comparison signal;
One or the gate logic unit, be connected in this soft start-up unit, this first comparator, this first with gate logic unit and this second and gate logic unit, with this starting-up signal and this first comparison signal work or logical operation;
One second comparator, be connected in this sampling keeping unit, this waveform generator, this first with gate logic unit and this second and gate logic unit, relatively this sawtooth waveform signal and this Voltage Feedback inhibit signal are exported one second comparison signal; And
One control unit when quiet, be connected in this waveform generator, this first and lock logical block and this second and gate logic unit, receive this sawtooth waveform signal, export one and adjust signal when quiet.
2, push-pull type control signal generation circuit according to claim 1 is characterized in that, also includes a constant-current source and is connected to this error amplifier by a switching switch, and a fixing electric current is provided.
3, push-pull type control signal generation circuit according to claim 1 is characterized in that, also includes a voltage-adjusting unit and is connected in this DC power supply, and provide circuit working required electric power.
4, push-pull type control signal generation circuit according to claim 1 is characterized in that, this soft start-up unit includes:
One counter is in order to the counting available machine time; And
One digital/analog converter is exported the available machine time with analog form.
5, push-pull type control signal generation circuit according to claim 1 is characterized in that, this circuit protection unit includes:
One under-voltage protection circuit is according to the under-voltage protection of this feedback signal as circuit;
One temperature protection circuit is according to the overtemperature protection of this feedback signal as circuit;
One excess voltage protection is according to the overvoltage protection of this feedback signal as circuit; And
One fluorescent tube open loop protection circuit is according to the protection of this feedback signal as load open circuit.
6, push-pull type control signal generation circuit according to claim 5 is characterized in that, this excess voltage protection is controlled the keying of this diverter switch.
7, push-pull type control signal generation circuit according to claim 1 is characterized in that, this load is a cold cathode fluorescent lamp pipe.
8, a kind of push-pull type control signal production method includes:
Produce a sawtooth waveform signal, obtain by a waveform generator;
Produce a clock signal, obtain according to this sawtooth waveform signal by a clock generator;
Produce a reverse clock signal, obtain through a not gate by this clock signal;
Produce one and adjust signal when quiet, control unit obtains according to this sawtooth waveform signal when quiet by one;
Sampling also keeps a voltage feedback signal, is connected to a feedback circuit by a sampling keeping unit by an error amplifier and obtains;
Relatively this voltage feedback signal and this sawtooth waveform signal are carried out by one second comparator, and are exported one second comparison signal;
Count this clock signal, and export a count signal and a starting-up signal, carry out by a soft start-up unit;
Relatively this count signal and this sawtooth waveform signal are carried out by one first comparator, and are exported one first comparison signal;
Produce one or gate signal, by this starting-up signal and the execution of this first comparison signal or logical operation;
Produce one first control signal, adjust signal, this second comparison signal, this clock signal and this or gate signal by this when quiet and carry out long-pending logical operation; And
Produce one second control signal, adjust signal, this second comparison signal, this reverse clock signal and this or gate signal by this when quiet and carry out long-pending logical operation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410029916 CN1677827A (en) | 2004-03-29 | 2004-03-29 | Push-upll control signal generating circuit and method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410029916 CN1677827A (en) | 2004-03-29 | 2004-03-29 | Push-upll control signal generating circuit and method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1677827A true CN1677827A (en) | 2005-10-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200410029916 Pending CN1677827A (en) | 2004-03-29 | 2004-03-29 | Push-upll control signal generating circuit and method thereof |
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| Country | Link |
|---|---|
| CN (1) | CN1677827A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110825017A (en) * | 2018-08-07 | 2020-02-21 | 三星电子株式会社 | Apparatus including security logic and method of operating the same |
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2004
- 2004-03-29 CN CN 200410029916 patent/CN1677827A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110825017A (en) * | 2018-08-07 | 2020-02-21 | 三星电子株式会社 | Apparatus including security logic and method of operating the same |
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