TWI283804B - An over-voltage protection apparatus for power converters - Google Patents

Abstract

The present invention proposes an over-voltage protection apparatus for power converter. An oscillator outputs a clock signal. By comparing a sense signal and a threshold signal, an over-voltage comparative unit generates a protection signal to an accumulating trigger unit. The accumulating trigger unit is accumulating and counting the protection signal in response to the clock signal. The accumulating trigger unit further generates an off signal to a latch unit as a period of the protection signal reaches a predetermined clock counts. In response to the off signal, the latch unit outputs a latch signal to a driving output unit for disabling a switching signal to a power switch. Therefore, the power switch is turned off and the over-voltage protection can be accomplished.

Description

1283804 IX. Description of the Invention: [Technical Field] The present invention is an overvoltage protection device for an overvoltage protection supply. Especially refers to one applied to the power supply

[Prior Art] At present, various power supply units, switches, and, and the like, provide stable voltage and lightning. In order to comply with the safety of the safety, the power supply must provide overvoltage to ensure that the output voltage is too high when the feedback is open, and the power supply is limited by the power supply. The supplier's second test is a schematic diagram of the conventional power supply. This power supply is used by the switching controller q to control the source supply. Resistor ^ ^ Each CsT provides an initial power supply, and the wire starts the switching controller to cut. Fixed light power supply _ voltage V. The _ type controller uses ‘two supply power switch Q1 to switch—transform 11 Τι. The auxiliary winding Να, the secondary winding ΝΡ and the secondary winding Ns. After the switching of H 1 , the auxiliary winding A generates a reflected voltage VAUx : the body rectifier provides power to the city controller A. The lion, % and the wheel (four) pressure V ° are closely related, so in the supply switching: supply double Vdd also with the output voltage V. There is a secret _ relationship. In the 7 Ul _ grant FB ′ according to the feedback signal Vfb, the switching source supply is called (10) connected to the electrical output 1 output voltage v 〇, the output voltage V 〇 through the optocoupler 1283804

DD Κΐ^χ(ν〇+νρ)]-ν〇复..................(1) 2 vF is the forward voltage drop of the wheel-out diode rectifier Dg; Vd Diode RectifierTM ItT TMAUX^?Mil Ti

S is the number of winding turns of the secondary winding Ns of the squeezing device T!. SUMMARY OF THE INVENTION In view of this, the present invention provides an overvoltage protection application.

By the use of no lighter than the fresh light (four) Lang Lang; = high mis-sports, and then through the progressive count misoperation, the occurrence time of the second field reaches a preset value, the present invention over the house protection device: cycle The power-off signal of the power cut-off device is used to turn off the output voltage, and the power supply for the lock is cut off! The drive signal, (4) depends on the output for protection action. The overvoltage protection device of the present invention includes a vibrating device wheel-to-clock signal, and the 'use-overvoltage signal is used to compare the unit's spine_sensing signal and the second critical signal, and after comparing the sensing signal and the critical signal, A protection signal is output. The protection signal is transmitted to a progressive trigger unit. The progressive triggering unit progressively counts the protection signal, and when the count of the protection signal reaches a preset value, a turn-off signal is sent to the flash lock unit, and the flash lock unit generates a flash lock signal to the drive signal generation unit. To stop outputting the drive signal to the power switch. 7 1283804 The overvoltage protection device of the invention not only provides the power supply device to cause the power supply to generate protection action when the feedback open circuit and the supply voltage are too high, but also can prevent the load end from being specific to the specific time through the progressive counting malfunction. Fortunately, when the output voltage is large, improper protection is performed. Therefore, the overvoltage protection circuit of the present invention can provide the most complete protection scheme for power supply. [Embodiment] Please refer to the second figure, which is a schematic diagram of the circuit architecture of the present invention. The overvoltage protection device of the present invention is used in a power supply device, comprising: an overvoltage signal to draw a comparison unit test signal and compare it with a -critical signal to generate a protection signal sPT; - a progressive trigger unit 28 The connection to the overvoltage signal age comparison unit and the oscillator 22' is used to receive the protection signal according to the -clock signal CLK to progressively count the protection signal sPT. When the count of the protection signal SPT reaches a preset value, the progressive trigger unit 28 outputs a cutoff signal SOTF; the lock unit 21 is connected to the progressive trigger unit Lu 28's receive cutoff signal S0FF to generate a lock signal LATCH; A driving signal generating unit 7G 10 is connected to the question locking unit 21 and the vibrating unit 22, and receives the clock signal CLK and the flash lock signal LATCH for stopping outputting a driving signal Vp to a power _ Ql for closing Output voltage V. The driving signal generating unit 25 is connected to the driving signal generating unit 1 , and receives a supply voltage sensing signal vB and a second critical signal Vt2 , and the second critical signal VT2 is the power supply. The limit value of the peak output voltage v〇. When the supply voltage sensing sfl number VB rises to the second critical signal Vn, the driving signal control unit 8 1283804 25 outputs a clear signal CLR to the driving signal generating material 1 () for periodically turning off the driving signal vPWMa power on (5) Qi, The peak output voltage V〇 of the power supply is thus limited to achieve overvoltage protection. Referring to the second figure, wherein the overvoltage protection device of the present invention further includes a reset unit 70 24 connected to a supply voltage Vdd, the latch unit 21 and the oscillator 22, receiving the clock signal CLK and the latch signal LATCH, and A set time is outputted to the challenge lock _ 兀 21 for resetting the output of the latch unit 21 within a set time after receiving the latch signal LATCH. The reset unit 24 is further connected to a supply voltage vDD, and when the amount of voltage supplied from the supply voltage Vdd is insufficient, a low voltage signal is received to output a reset signal RST to the latch unit 21. The third figure is a schematic block diagram of a circuit according to a first embodiment of the present invention. The overvoltage signal acquisition unit 23 receives an initial threshold signal Vti for one of the overvoltage comparators 231, and the other input receives a supply voltage sensing signal of ¥6. The first threshold signal vT1 and the supply voltage sensing signal Vb are compared to output a first protection signal # to the progressive trigger unit 28. When the power supply supplier has a feedback open circuit and the output voltage is too high, since the reflected voltage vAUX is closely related to the output voltage v〇, the supply voltage VDD at the supply terminal VDD also rises, thereby making the supply The value of the voltage sensing signal vB is also relatively increased. Therefore, in the first embodiment, the correspondence relationship is utilized, so that the Xiao_over ratio (four) 231 is used as the over-the-surface matching unit 23, and the first critical city Vti is designed. Wire adjusts the critical limit of the power supply output voltage. When the value of the supply voltage sensing signal Vb is greater than the first critical signal 9

The potential clear signal CLR to the driving signal generating unit 1 〇 causes the driving signal VpWM to be low, thereby turning off the power switch , to provide a driving signal for periodically turning off the power supply to limit the wheeling voltage. In the above description, the first embodiment of the present invention reaches the progressive trigger by supplying the voltage sensing signal VB to the duration of the first critical signal VT1 when the output voltage V is too high when the power supply is opened and the output voltage V is too high. When the preset value of unit 28 is 1,283,804 vT1, the overvoltage comparator 231 will go to the progressive triggering unit 28, at this time, the accumulation of the protection signal % sPT1, and the accumulation of the protection element 28, the first protection message arrives. After the preset value, the 28th ceremonial-protection signal Sm is sent to the driving signal generating unit 1G to stop the output driving signal vPW_the power listening domain generating unit 10 needs to lose a large amount of time. Itll: 1 when using the pressure and the field is free of charge. Its towel _ ^ ' reaches the power supply. The pre-W value is the number of cycles Tcount.雍己u - Figure 11 is a schematic diagram of the circuit waveform of the present invention. When the power supply # = factory life road (four) (four) pressure V. Tear, persimmon; ^,, increase. At time 1^, the sense signal is supplied: 4 L. At Vti', the overvoltage comparator 231 outputs a low-level first-protection signal % to the progressive trigger unit 28. Next, the progressive triggering unit 28 starts the action of the progressive ritual to prepare for the flashing of the transcription number generating unit 10. Then, at time T2~T3, the feedback open circuit makes the supply voltage sensing signal VB_ rise to the threat time μ, and the supply cake_signal% will top to the second critical extinction Vt2. Low output

The circuit block diagram 23 of the second embodiment is a feedback comparator 232, a triple critical signal VT3, and another input map. The overvoltage signal acquisition unit 23 receives a third terminal to receive a voltage feedback sensing signal vFB, and the VT3 and the voltage feedback sensing signal VFB, to the The trigger unit 28 is progressive. Comparing and calculating the third critical signal for rotating a second protection signal s. The Hita power supply is turned on and the circuit is turned on, and the voltage of the feedback feedback signal Vfb is relatively high. Therefore, in the second embodiment, the corresponding comparator 232 is used, and the value of the second critical signal VT3 is designed to limit the peak output voltage of the power supply. When the value of the voltage feedback sensing signal vFB is greater than the third critical signal Vt3, the feedback ratio: 232 outputs the first second protection signal sPT2 to the progressive triggering unit 28, and the progressive triggering unit 28 performs The progressive count of the second protection signal SpT2. After the progressive triggering unit 28 counts the second protection signal SpT2 to reach a predetermined value, a cutoff signal S0FF is outputted to the latching unit 21 to flash lock the driving signal generating unit 1 such that the driving signal generating unit 10 Stop outputting the drive signal VpwM to the power switch Qi to avoid improper protection when the load terminal needs a large output voltage within a certain time to achieve the actual overvoltage protection of the power supply. In the above description, the second embodiment of the present invention is based on the voltage feedback sensing signal vFB to the third threshold when the power supply supplies the output power to the load.

After the duration of the signal % reaches the preset value of the progressive trigger unit 28 (ie, the counting period tco 丽), the current (fourth) voltage tilting device age stops the touch drive secret number VpwM to the power off Ql, and the base is stopped as the voltage reaches the source supply. The actual overvoltage protection. Furthermore, the circuit operation principle and waveform of the second embodiment of the present invention are the same as those of the first embodiment except that the protection signal & source received by the progressive trigger unit 28 is different, and the rest are the same. . With reference to the second figure, the sixth figure is a schematic diagram of the circuit block of the third embodiment of the invention. The overvoltage signal acquisition comparison unit 23 is composed of an overvoltage comparator 23 and a feedback comparator 232 and a connection unit 233. The overvoltage comparator 231 compares and calculates a first critical signal vT1 and a supply voltage sensing signal Vb for generating a first protection signal SpTi; the feedback comparator 232 compares a third critical signal Vt3 with a voltage feedback The sensing signal Vfb is used to generate a second protection signal SPT2; the connecting unit 233 is connected to the overvoltage comparator 231, the feedback comparator 232 and the progressive triggering unit 28, and the first protection signal SpTi is The second protection signal SpT2 is transmitted to the progressive trigger unit 28. When the output terminal is open and the output voltage V is too high, the values of the supply voltage sensing signal Vb and the voltage feedback sensing signal Vfb are relatively increased, and thus are utilized in the third embodiment. In this correspondence, an overvoltage signal acquisition unit 23 composed of an overvoltage comparator 231, a feedback comparator 232 and a connection unit 233 is used, and the first critical signal Vn and the second critical signal Vts are simultaneously designed. The value is used to adjust the critical limit of the power supply output voltage 0 12 ΐ 28 * 3 δ 〇 4 million supply voltage sensing signal ν Β value is greater than the first critical signal ν τι, the over-powered Chubi 231 231 generates the first protection signal sPT1; or When the value of the voltage feedback sensing signal Vfb is greater than the second critical signal vTS, the feedback comparator 2^2 also generates a second guarantee, signal SPT2. The first protection signal "and the second protection signal - the protection signal SpT' is formed by the connection unit 233 and then transmitted to the progressive trigger unit 8. At this time, the progressive trigger unit μ performs the progressive counting of the protection signal & After the SPT count reaches a preset value (ie, the counting period Τ_τ), the output > - cutoff signal SGFF_off unit 21 is used to perform the flash lock by the charm signal generating unit 1 so that the driving signal generating unit 1 stops the output driving. Signal %] force rate switch Qi 'to avoid improper protection when the load terminal needs a large output voltage within a certain time' to reach the actual overvoltage protection of the power supply. In the above description, the third embodiment of the present invention is in the power supply The supplier provides the output f rate to the load, by supplying the voltage sensing signal % to the duration of the first critical tVT1 and the voltage feedback sensing signal VFB is topped to the third critical signal, ^% of __ Whether there is overvoltage phenomenon in the power supply of Laisaki, if the temple: reaches the preset value of the progressive triggering list 728 (ie, miscellaneous Τ _τ) ^ Guan I Ming will pass the light protection county will stop taking the 峨 峨 VpwM to the work = Inter-service output light Vq, which is protected by the actual power supply of the shaft power supply. The road diagram 'the seventh diagram is the progressive trigger unit of the present invention—the embodiment of the electric, block diagram. The progressive trigger unit 28 includes A sustaining unit 284 is connected to the overvoltage signal acquisition unit 23 and the processor 22, and receives the protection signal PT A and calls CLK' to delay the state of the protection signal & and outputs a 13 1283804 up and down signal UP. /DOWN. A top-and-bottom counting unit 282 is connected to the maintaining unit 284 and the oscillator 22, and receives the up-and-down signal UP/D0WN and the clock signal CLK for the tens of operations. The upper and lower counting unit 282 is based on the up-and-down signal up/D〇WN The ON/OFF unit 282 can be counted up, and the upper and lower counting units can be counted down according to the deactivation (0FF) of the up and down signals UP/DOWN, and the counting is stopped at the end of the downward direction. At the end of the upward counting, the output of the high potential is turned off, and the switching frequency of the CLKm mosquito driving signal Vpwm is maintained and the holding time of the maintaining unit 284. The maintaining unit 284 in the above description is composed of two D-type flip-flops 2842.盥 2844 To achieve, when the sustain unit 284 is connected to the _ low potential rake number &, in order to prevent the ground bGunee or switching spike noise, the maintenance unit 284 needs to cooperate with the oscillator. 22 generates the clock signal CLK, when (4) Laicheng & (4), and outputs the high-level signal UP/DOWN. The second reference picture of the flash-lock unit 21 can be used by a D-type flip-flop The clock terminal is connected to the accumulating unit 28, and receives the truncation of the high level: the signal S〇FF is used to output the (10) signal latch of the low level. The low-level flash lock signal LATCH is connected to the D input of one of the d-type positive and negative crying (9) in the driving signal generating unit 1〇, so that the D-type positive and negative _D input terminal is low, and thus the driving signal is Produce Itg 1G A iron stop shaft VpwM, and ask for the purpose of lock protection. When the power supply is protected by _, the electronics connected to its output will not function properly. ^ With the first figure, please refer to the eighth figure, which is a block diagram of the reset unit circuit 1283804 of the present invention. The reset unit 24 used in the overvoltage protection device of the present invention is connected to the latch unit 21, and the reset signal RST of the low potential can be turned on in two ways to reset the latch unit 21. The reset unit 24 can restart the supply power VDD according to the power supply of the power supply to turn off the reset signal RST for resetting the latch unit 21. The reset unit 24 may also output a reset signal RST for resetting the latch unit 21 according to the generation of the flash lock signal LATCH. The reset unit 24 includes voltage dividing resistors composed of transistors 2401, 2402, and 2403 connected in series to each other for outputting a low voltage signal Vlv that reflects a lower supply voltage Vdd. The low voltage signal Vlv controls the turn-on or turn-off of the transistor 2412 through the inverter 2405. Once the supply voltage Vdd is available, and the transistor 2412 is turned off, the constant current source 2411 charges the reset capacitor 2413. Two NAND gates 2415 and 2416 form an SR register. The first input terminals of NAND gates 2415 and 2416 are coupled to the outputs of NAND gates 2410 and 2415, respectively. A second input of NAND gate 2416 is coupled to reset capacitor 2413. Through the inverter 2404, the second input of the NAND gate 2415 is coupled to the clock signal CLK of the oscillator 22. At the output of the NAND gate 2415, a low potential reset signal RST is generated in accordance with the low potential on the reset capacitor 2413. When the reset capacitor 2413 is charged to a high potential, the reset signal RST is deactivated and the clock signal CLK is generated. The capacitance value of the reset capacitor 2413 and the current value of the constant current source 2411 determine the pulse width of the reset signal RST. The reset unit 24 in turn includes a transistor 2414, an inverter 2417, and a timer 2418. The transistor 2414 is connected in parallel with the reset capacitor 2413 for discharging the reset 15 1283804 capacitor 2413. The output of timer 2418 controls the turn-on or turn-off of transistor 2414. The clock terminal of the timer 2418 is coupled to the clock signal CLK for generating the time delay in accordance with the time reference of the clock signal CLK. Through the reverse phase 芎 2417 'the reset end of the timer 2418 is connected to the latch signal LATCH, according to the deactivation (high potential) of the lock signal LATCH, the reset terminal of the timer 2418 is low, and the output of the timer 2418 is At low potential, the transistor 2414 is off. ~ The latch signal LATCH is enabled (low potential), the reset terminal of timer 2418 is high, and timer 2418 is also enabled. When the timer 2418 reaches its set time, the output of the timer 2418 is high, the transistor 2414 will be turned on to discharge the reset capacitor 2413, and a reset signal RST is generated to reset the latch unit 21. In summary, the overvoltage protection device of the present invention not only provides a power supply to cause the power supply to generate a protection action when the feedback open circuit and the supply voltage are too high, but also can prevent the load from being generated by the duration of the progressive count malfunction. Improper protection when a large output voltage is required for a specific time. Therefore, the overvoltage protection circuit of the present invention can provide the most complete protection scheme for the power supply. 16 1283804 [Simplified description of the drawings]: The first figure is a schematic diagram of a conventional power supply; the second figure is a schematic diagram of a circuit structure of the present invention; the third figure is a circuit block diagram of the first embodiment of the present invention; 5 is a circuit block diagram of a second embodiment of the present invention; FIG. 6 is a circuit block diagram of a third embodiment of the present invention; and FIG. 7 is a circuit block diagram of a progressive trigger unit of the present invention; Eight Diagrams are block diagrams of the reset unit circuit of the present invention. [Main component symbol description] Latch unit 21 Oscillator 22 Overvoltage signal acquisition comparison unit 23 Reset unit 24 Drive signal control unit 25 Progressive trigger unit 28 Drive signal generation unit 10 Current comparator 231 Voltage comparator 232 Connection unit 233 Up-and-down counting unit 282 Maintenance unit 284 17 1283804 D-type flip-flops 2842, 2844 transistors 2401, 2402, 2403, 2412, 2414 Inverters 2404, 2405, 2417 Capacitor 2413 Constant current source 2411 NAND gate 2415, 2416 Timer 2418 φ Transformer 1 Switching controller Ui Sensing resistor Rs Current sensing signal Vcs Feedback signal VpB Reflecting voltage Vaux Power switch (^ _ Supply voltage Vin Current sensing signal vcs Voltage feedback sensing signal vFB Second critical signal Vt2 Heavy Set signal RST clock signal CLK drive signal VpwM power switch (^ 18 1283804 protection signal SPT cutoff signal S〇FF latch signal LATCH supply voltage Vdd first critical signal Vti first protection signal Spti third critical signal Vt3 • second protection Signal sPT2

Clear signal CLR

Claims (1)

!2838〇4 - +'Scope of application: L type of overvoltage protection device, used in a power supply, to obtain a sensing signal, including: an oscillator, outputting a clock signal; overvoltage signal acquisition Comparing unit, the sensing signal is compared and compared with a threshold signal for outputting a protection signal; a progressive triggering unit is connected to the overvoltage signal capturing unit and the oscillator, Receiving the protection signal and the clock signal, and progressively counting the protection signal, and after the protection signal reaches a preset value, outputting a wear signal; a latch unit connected to the progressive trigger unit Receiving the cutoff signal, a latching signal is rotated; a driving signal generating unit is connected to the latching unit and the oscillator, and receives the clock signal and the latching signal to stop outputting a driving signal And a driving signal control unit connected to the driving signal generating unit to receive the side sensing signal and a second threshold signal, when the sensing signal When the second threshold signal is raised, the driving signal control unit outputs a clear signal to the driving signal generating unit for turning off the driving signal to the power switch; wherein the (10) unit is a lion driving job generating unit, The drive signal is turned off by the flash lock to the power switch. 2. The overvoltage protection device according to the scope of claim 2, further comprising a reset unit connected to the fresh element and the vibration, receiving the time pulse 20 Ϊ 283804 and the latch nickname, and receiving A reset signal is outputted to the latch unit for resetting the latch unit within a set time of the latch signal. 3. The overvoltage protection device according to claim 2, wherein the reset unit further connects a supply voltage, and receives a low voltage signal according to the power supply after the power supply is restarted to output a weight. The signal is sent to the challenge unit for resetting the latch unit. 4. The overvoltage protection device according to item 1 of the patent application scope, wherein the overvoltage signal acquisition unit is an overvoltage comparator, and the comparison operation is a first threshold and a supply voltage sensing. The signal is used to output a -first protection signal to the progressive trigger unit. 5. If you apply for the overvoltage ship device described in the special item, the over-voltage signal is compared with the fresh element-review comparator, which is a comparison between the three critical signals and the voltage feedback. The test signal is used to output a second protection signal to the progressive trigger unit. 6. The invention relates to an overvoltage protection device as described in item i, wherein the overvoltage signal acquisition unit comprises: an overvoltage comparator, which compares a first critical signal with a supply voltage sense a test signal for outputting a first protection signal; - a feedback comparison n, a comparison operation - a third critical signal and a voltage feedback sensing signal for outputting a second protection signal; and a connection sequence 7L, The first protection signal and the second protection signal are transmitted to the 5H progressive trigger unit. The first voltage protection signal and the second protection signal are transmitted to the overvoltage comparator, the feedback comparator and the progressive trigger unit. The invention relates to the overvoltage protection device of claim 1, wherein the progressive triggering unit comprises: a maintaining unit connected to the overvoltage signal capturing unit and the oscillator, and receiving the The protection signal and the clock signal are used to delay the state of the protection signal, and output an up and down signal, and a top and bottom counting unit connected to the maintaining unit and the oscillator to receive the up and down signal and the clock signal In order to perform the counting operation, and counting down the knot, the tree stops the miscellaneous 'in the top of the tree (four) job stop signal. 8. The overvoltage protection device according to claim 7, wherein the upper and lower leaves are counted upward according to the up and down signal, and the count is counted down according to the stop of the upper number. twenty two