TWM278145U - An over-voltage protection apparatus for power converters - Google Patents

Description

M278145 IX. New type description: [Technical field to which the new type belongs] This creation is an over-voltage protection device. ^ The over-voltage device of the supplier depends on the device. For power supply [Previous technology] At present, various power supply devices have been used. In order to meet the safety regulations, the voltage and electricity for stable adjustment

Protection function to ensure that Niu Sheng ^ ^ ^ for the wire to provide over-voltage operation, by limiting the power out of the power supply wheel = = high-speed misoperation itself and the power system. The corresponding power supply should be two, one picture, which is a schematic diagram of a conventional power supply. The power supply

Capacitance: Two: Type: The working system is Ul, which is used to control the power supply. Resistor RST is the initial power supply to start the switching controller switch. $ 长, 疋 adjust the output voltage v of the power supply, the switching controller switches to produce a switching PWMv power supply switch Qi, used for city-reliance transformer auxiliary winding Na, secondary-side winding Np and secondary failure group two After the switching of Ai T !, the auxiliary winding 仏 generates a reflected voltage Vaux, which is further supplied by a pole m Da to provide power to the switching controller Ui. Since the reflected voltage VAUX is closely related to the output voltage v0, the supply voltage & at the supply terminal VDD is also closely related to the output voltage. At the switching control FB ^ ㈣ end FB, the pulse width of the switching signal VPWM is stably adjusted according to the feedback signal Vfb. An error amplifier 80 is connected to the power supply input terminal {to obtain an output voltage and an output voltage V. Through the smooth surface M278145 combiner 90 to obtain the feedback signal vFB, the switching controller recognizes the feedback signal

Vfb allows the output voltage v of the power supply to be stably adjusted. The supply voltage Vdd can be expressed as: _ (1) V〇D " [: ^ x (V〇 + Vf)]-Vd where VF is the forward voltage drop of the output diode rectifier D0; Vd is the diode rectifier The forward voltage drop of Da; TNAUX is the winding resistance of the auxiliary winding Naux of the transformer Tl; TNS is the number of winding turns of the secondary winding Ns of the transformer Tl. [New content] In view of this, this invention creates an over-voltage protection device that is applied to the power supply. It confirms that the power supply has a malfunction due to feedback open circuit and excessive supply voltage through different comparison levels, and then progresses through Count the duration of the malfunction. When the duration of the occurrence reaches a preset value, the overvoltage protection device can periodically cut off the drive signal of the power supply to limit the output voltage and provide a latch to cut off the power supply. The driving signal is used to latch off the output voltage, and φ is used for protection. This creative overvoltage protection device includes an oscillator to output a clock signal. At the same time, an overvoltage signal acquisition and comparison unit is used to capture a sensing signal and a critical signal. After the comparison operation, the sensing signal and the critical signal are output. A protection signal. The protection signal is transmitted to a progressive trigger unit. The progressive trigger unit counts the protection signal progressively. After the protection signal count reaches a preset value, it turns out a wear signal to a latch unit. The latch unit generates a latch signal to a drive signal generation unit. To stop outputting the drive signal to the power switch. M278145 This creative protection device not only provides the power supply when the feedback circuit is open and the power supply is too high, it will cause the power supply to produce a protective action. It can also count the duration of the malfunction in order to avoid the load end at a specific time. Do you need improper protection when you need a large output power? Therefore, this author has provided the most complete solution for power supply. [Embodiment] Examine the second diagram, which is a schematic diagram of the creative circuit architecture. This creative over-voltage protection device is made on the power supply pin, which guarantees that:-the signal over the surface is transmitted through the -23 voltage divider (composed of a resistor Ra and a resistor Rb) and- The critical signal is used for comparison operation to generate a protection signal sPT. The -progressive trigger unit 28 is connected to the overvoltage signal extraction comparison unit μ and -oscillation H 22, which is used to receive the Lai signal to progress according to the clock signal CLK. Count protection signal SPT. After the count of Tianbaokou 蒦 Λ SPT reaches a preset value, the output of the progressive triggering unit M is cut off to Tiger S0FF, and a flash lock unit 21 is connected to the progressive triggering unit 28 'receiving the cutoff signal s. ff 'Latch to generate a question lock signal and drive a drive generation unit το 10 is connected to the unit 21 and the oscillation || 22, which is to receive the clock signal CLK and the question lock signal LATCH to stop outputting a drive signal ^ Cong to- The power switch Q1 is used to flash-lock the cut-off output voltage% to achieve over-voltage protection; and-the driving signal control unit 25 is connected to the driving signal generating unit 10 and receives and supplies a voltage sensing signal Vb and a second critical signal γη, The second critical signal is the limit value of the peak output voltage% of the power supply. When the power is supplied, the sensing is -l; vb_l rises to two critical signals. N The driving signal control unit M278145 25 outputs a clear signal CLR to the driving signal. The Λ number is generated as early as 10, which is used to periodically cut off the drive signal VPWM to the power switch η + Q. The peak output voltage V of the power supply is therefore limited to achieve over-voltage protection. 'Among them, the overvoltage protection device further includes a reset unit 24 connected to the supply voltage Vdd, _ unit 21 and Zhenying cry 22, which is connected to the temple pulse signal CLK _ lock signal latch and receives the ^ signal. After LATCH-Setting_, Output—Reset signal Liaolang lock sheet 70 2 is used to reset the output of the lock unit 21. The reset unit% is further connected to the supply voltage VDD and when the amount of voltage provided by the supply voltage Vdd is insufficient Receiving-low voltage, resetting the Etengpeng lock unit 2 with the first $ 'The second picture is the circuit diagram of the first embodiment of the creation. The over-voltage signal capture comparison unit 23 ―Over voltage More: 23 Bu ϋ one over-voltage comparator 231 receives a first input signal% threshold, the other input receives - supply voltage sensing signal% as first threshold comparison operation

The signal VT # supplies the voltage sensing signal Vb for outputting the first protection signal ^ to the progressive trigger unit 28. When the output voltage of V0 is too high due to an open circuit of the power supply, the reflected voltage vAUX and the input voltage v are caused. There is a correction system. Therefore, the supply money Vdd on the supply side Vdd is also rising, and the value of the supply voltage sensing signal VB is also relatively increased. Therefore, in this section-the implementation of the radio system _ this correspondence relationship ' The over-voltage comparator 231 is used as the over-voltage dragon operation comparison unit 2 to adjust the critical limit of the output voltage of the power supply by the value of the first critical signal VT1 on the same day. #Supply LaiM signal VB is greater than the -threshold signal M278145 vT1, the over-voltage comparator 231 will output the first protection signal SpTi to the progressive trigger unit 28 for the first time, at this time the progressive trigger unit 28 performs the first Progressive count of the protection signal sPT1 'When the progressive trigger unit 28 counts the first protection signal SpTi to a preset value, it outputs a cut-off signal S0FF to the latch unit 21 to latch the drive signal generation unit 10 so that The drive signal generating unit stops outputting the drive signal VpWM to the power switch to avoid improper protection when the load end needs a large output voltage within a certain time, to achieve the actual overvoltage protection of the power supply Φ. Wherein the preset value is a counting period of 01; ^. In conjunction with the third figure, the fourth figure is a schematic waveform diagram of the creative circuit. When the output voltage of the power supply is too high due to an open feedback loop, the supply voltage vDD also increases at the time of ~ 2. At time τ2, the supply voltage sensing signal νB will reach the first critical signal vTl. At this time, the over-voltage comparator outputs a low-level first protection signal SpT1 to the progressive trigger unit 28. Next, the progressive trigger unit 28 starts the progressive counting operation in preparation for flash-locking the drive signal generating unit 10. Furthermore, at time I ~ A, the feedback open circuit makes the supply voltage sensing signal vB continue to rise, and at time 3, the supply voltage_signal%

Will reach the second critical signal V17, at this time the drive signal control unit 25 will output a low-level clear signal CLR to the drive signal generating unit 10, so that the drive signal VpwM is low, and then the power switch Qi is turned off to provide Periodically cut off the drive signal for the power supply to limit the output voltage. In the above description, the first embodiment of the present invention is that when the output voltage V0 is too high due to the feedback switch-on of the power supply, the duration from the supply voltage sensing signal VB to the first critical signal VT1 reaches progressive. After the preset value M278145 of the triggering unit 28 (that is, the counting period Tcount), the overvoltage protection device of this creation will stop outputting the drive signal VPWM to the power switch Ql to latch off the output voltage ^ 〇, = to reach the power supply Actual overvoltage protection. In conjunction with the second diagram, the fifth diagram is a circuit block diagram of the second embodiment of the creation. Wherein, the overvoltage signal acquisition and comparison unit 23 is a feedback comparison boundary = 2th think of the feedback comparator 232-the input end receives-the third critical signal Vt3, ^ 1 loses 2

The PT2 receiving-voltage feedback sensing signal vFB is used to compare and calculate the third threshold: the signal Vt3 and the voltage feedback sensing signal VFB, which are used to output a second protection signal s a to the progressive trigger unit 28. ~ When the feedback voltage of the field power supply is too high, the value of the voltage feedback sensing signal VFB will be relatively increased. Therefore, this correspondence relationship is used in the second embodiment. A feedback comparator, 232, is used to simultaneously design the value of the three critical signal VT3. When the value of the voltage feedback sense hemp VFB is greater than the third critical threshold, the feedback comparator 232 will output the first-time second protection signal to the progressive trigger unit, and the progressive collision unit 28 will now Progressive counting of the second protection signal-. When the progressive contact order it 28 4th—the security signal sPT2 arrives—the preset value, a cut-off signal s0FF is output to the interrogation unit 21 to interrogate the drive signal generation unit 10 so that the drive signal Generate single magic G to stop output driving signal% Wei Shi I power rate switch Q! 'To avoid the need for a large output voltage to protect the load during a certain period of time, improper protection, and make the actual power over-power protection. … In the above description, the second embodiment of this creation is to provide output power to the load in the power supply, and the voltage feedback sensing signal Vfb is used to hold the third critical M278145 signal vT3. __ 赖 发 Unit_default value (That is, the counting period τ_ντμ 'is too old to rely on the device to stop as a crane signal ^ side-force. The switch Q!' Is called the lock-off output voltage V. It is used to achieve the over-voltage protection of the power supply. Compared with the first embodiment, the principle of the circuit operation and its waveform are compared with the first embodiment, 'the Lai signal received only by the progressive trigger unit 28 is different from the source, the rest are the same' and will not be repeated here. With the second figure, the The sixth figure shows the f block of the second embodiment of the creation. The overvoltage signal acquisition and comparison unit 23 is composed of an overvoltage comparator 23, a feedback comparator 232, and a connection unit 233. Overvoltage The comparator 231 compares the operation_the first critical signal vT1 and the supply voltage sensing domain% to generate a first protection signal ~ τι; the feedback comparison $ 232 comparison operation—the third critical signal% and the voltage feedback sense Telemetry signal vFB for generating The second protection signal "; the connection unit 233 is connected to the over-voltage comparator 231, the feedback comparator 232 and the progressive trigger unit 28 'to transmit the first protection signal sPT1 and the second protection signal SpT2 to the progressive Trigger unit 28. 菖 The power supply is open to the output terminal and the output voltage v0 is too high. The value of the supply voltage sensing signal vB and the voltage feedback sensing signal vFB will also be relatively increased. In the embodiment, this correspondence relationship is used, and an overvoltage signal acquisition and comparison unit 23 composed of an overvoltage comparator 231, a feedback comparator 232, and a connection unit 233 is used, and the first critical signal Vti and the first The value of the two critical sfl signal VT3 is used to adjust the critical limit of the output voltage of the power supply. 0 ⑧ M278145 When the value of the supply voltage sensing signal νΒ is greater than the first critical signal ντι, the overvoltage comparator 231 generates the first protection signal SPT1; or when When the value of the voltage feedback sensing signal VFB is greater than the third critical signal VT3, the feedback comparator 232 also generates a second protection signal SPT2. The first protection signal is 8 and the second protection is 8 No protection signal SPT SPT2 233 formed through the connecting unit, and then delivered to the trigger unit progressive

At this time, the progressive trigger unit 28 performs the progressive counting of the protection signal SPT. When the protection signal SPT count reaches a preset value (that is, the counting period tcount), a cut-off signal S0FF is output to the latch unit 21 to the drive signal generating unit 1.

'Flash lock' causes the drive signal generation unit 10 to stop outputting the drive signal VpWM to the power switch Qi, in order to avoid that the load end needs a large output voltage within a certain period of time to perform improper warranty and compliance to achieve the actual overvoltage of the power supply. protection. In the above description, the third embodiment of the present invention is that when the power supply provides output power to the load, the voltage sensing signal Vb reaches the first critical signal VT1 by the supply voltage, and Xialong _ Signal Vfb Issue No. The duration of the three critical signal VT3 is used to determine whether the power supply has an over-voltage phenomenon. If it is continuous, the unit will stop output driving after the over-voltage protection unit 28__ Jingjing counts the meaning of T_τ). The signal VPWM reaches the power ^ off Qi, and the output voltage VG is turned off to achieve power supply voltage protection. In conjunction with the second picture, the seventh picture is a block diagram of the progressive triggering unit of the creation. Progressive triggers include: “maintain unit 2 to over-voltage minus extraction and taste unit 23 and vibration”

Spt and the clock signal CLK, ㈣ f receive the state of the silk domain% protection edge flood SPT, and output a 13 M278145 up / down signal. An up-down counting unit 282 is connected to the maintenance unit 284 and the vibration gain 22 ′ to receive the up-down signal UP / DOWN and the clock signal CLK for counting operation. The up and down counting unit 282 can count up according to the enable (ON) of the up and down signals, and make the up and down counting unit 282 count down according to the disable (0FF) of the up and down signals, so that the up and down counting unit 282 can count down and Stop counting at the end of down counting, and output the cut-off of high potential minus sQFF at the end of up counting. Its frequency is the switching frequency of the VCLK driving signal VPWM and the sustaining time of the sustaining unit 284. The maintenance unit 284 in the above description is implemented by two D-type flip-flops and 2844. When the #maintenance unit 284 receives a low-level protection signal & In order to prevent the receipt of instantaneous ground bouncing or switching spike noise, the maintenance unit 284 needs to cooperate with the clock signal CLK 'time-series domain & UP / DOWN signal. Out of breath

The second reference "The unit _ can be implemented as a D-type flip-flop. Its clock end is connected to the _ tired_ send unit 28, which is the Wei high level cut-off signal S0FF to output the low level The relevant signal latch. The scale 5 tiger LATCH is connected to the D input terminal of one of the d-type flip-flops in the drive signal generating unit 10, so that the D input terminal of the D-type flip-flop is low potential. Unit U) ask Lai Zhihe'e __, ㈣ $ to protect the purpose. When the power supply is protected, the electronic devices at its output terminals will not operate normally. t With the second figure, please refer to the eighth figure, which is a block diagram of the reset unit circuit 14 M278145 for this creation. The reset unit 24 used in this creative over-voltage protection device is connected to the interlock unit 70. The system can output the reset signal of low potential by two methods. According to the restarting power of the power supply, the power supply Vdd can be restarted to output a reset signal RST for resetting the latch unit 21. The reset unit 24 may also output a reset signal RST ′ according to a set time after the latch signal LATCH is generated to reset the latch unit 21. _ The reset unit 24 includes a voltage-dividing resistor composed of transistors 2401, 2402, and 2403 connected in series to each other to output a low-voltage signal Vlv that reflects a lower supply voltage Vdd. Through the inverter 2405, the low-voltage signal Vlv controls the on / off of the transistor 2412. Once the supply voltage Vdd is available and the transistor 2412 is in the off state, the constant current source 2411 is used to charge the reset capacitor 2413. The two NAND gates 2415 and 2416 form an SR register. The first input terminals of the NAND gates 2415 and 2416 are connected to the output terminals of the NAND gates 2416 and 2415, respectively. The second input of the NAND gate 2416 is connected to the reset capacitor 2413. Through the inverter 2404, the second input terminal of the NAND gate 2415 is connected to the clock signal CLK of the oscillator 22. At the output of the NAND gate 2415, a low-level reset signal rSt is generated according to the low potential on the reset capacitor 2413. When the reset capacitor 2413 is charged to a high level, the reset signal RST is disabled and a clock signal CLK is generated. The capacitance 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 further includes a transistor 2414, an inverter 2417, and a timer 2418. The transistor 2414 is connected in parallel with the reset capacitor 2413 to discharge the reset 15 ④ M278145 capacitor lake. The round of ㈣2418 is expected to expire on the day of the day. The clock end of the timer 2418 is connected to the clock signal CLK, and the time gate 丞 + is used to generate the time delay according to the time reference of the day π pulse signal CLK. Through the inverse cry 24Π, the reset terminal of the timer 2418 is connected to ΛΙ 罝 鳊 connected to the latch signal LATCH. According to the disable (high potential) of the latch signal LATCH, the reset terminal of the normal state 2418 is low. The output of the timer period is low, and the transistor 2414 is turned off. 1 = The lock signal LATCH is the start-up potential), the timer is reset, and the timer 2418 will also be used as the start-up level. When the scale H 2418 reaches its sigh time, the rotation of the timer 2418 is ancient, and the transistor 2414 resets the guide τ, the electric valley 2413 into 4 and the lightning, -a., Asks the lock unit 21. "Electric shock" Yu Sheng resets the outline to reset the above-mentioned "This creative overvoltage protection device feedback open road record"; should respond to the bribe can cause the power supply 11 to produce a protective action, the door meat chef recognizes x It is not necessary to prevent the load end from happening at the same time. Objective ^ The slave circuit can be provided by Wei · The most complete ^ ⑧ 16 M278145 [Schematic description]: The first picture is a conventional one The schematic diagram of the power supply; the second diagram is the schematic diagram of the creative circuit architecture; the third diagram is the schematic circuit block diagram of the first embodiment of the creation; the fourth diagram is the waveform of the creative circuit is not intended; the fifth diagram is the second embodiment of the creation The schematic diagram of the circuit block; the sixth diagram is the schematic diagram of the third embodiment of the creation; the seventh diagram is the schematic diagram of the progressive trigger unit of the creation; and the eighth diagram is the schematic diagram of the reset unit circuit of the creation. [Main components Explanation of symbols] Latch unit 21 Oscillator 22 Overvoltage signal acquisition and 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 M278145 D Type inverter 2842, 2844 transistor 24 (H, 2402, 2403, 2412, 2414 inverter 2404, 2405, 2417 capacitor 2413 constant current source 2411 NAND gate 2415, 2416 timer 2418 φ transformer is a switching controller Ui Sense resistor Rs current sense signal Vcs feedback signal Vfb reflected voltage Vaux power switch (^

• Supply voltage vIN current sense signal Vcs voltage feedback sense signal Vfb second critical signal VT2 reset signal RST clock signal CLK drive signal Vpwm power switch 卩! ⑧ M278145

Protection signal SPT Cut-off signal S0ff Latch signal LATCH Supply voltage Vdd First critical signal Vti First protective signal SPT1 Third critical signal Vt3 • Second protective signal sPT2 Clear signal CLR

19 ⑧

Claims (1)

M278145 10. Scope of patent application: i- a kind of over-voltage protection device, so that a sensor signal is obtained in the Lin-power supply, including: an oscillator that outputs a clock signal; an over-voltage signal acquisition and comparison unit 'Department_take the sensing signal and compare it with a more critical signal. Hx round out—Lai signal;-Progressive trigger unit, connected to the overvoltage signal acquisition comparison unit disk vibrating III' is receiving the protective tank And the clock signal, and count the protection signal progressively, and output a cut-off signal after the count of the protection signal reaches a preset value;-a flash lock unit, connected to the progressive trigger unit, is connected to the cut-off signal, Output 'a flash lock signal; a drive signal generating unit connected to the __ unit and the vibrator, which receives the clock signal and the flash lock signal' to stop outputting a drive signal to a power switch; and a drive signal The control unit is connected to the driving signal generating unit and receives a brewing tank and a second critical signal. When the sensing signal rises to the second critical signal, the driving signal is controlled. Element Output - clear signal to the driving signal generation unit to turn off the drive signal to the power switch; wherein 'the _ units based control relay driving signal generating unit, silk to ask a lock cut-off the driving signal to the power switch. 2. The over-voltage protection device as described in item 丨 of Shenyan's patent scope, further comprising a reset unit connected to the latch unit and the vibrator, receiving the clock signal and the latch signal, and Within a set time after receiving the latch signal, a reset signal is output to the latch unit for resetting the latch unit. 20 M278145 3 · As in the scope of the patent application No. 2 of the evening, wind $ # 一 + ...: the over-pressure protection device, where the reset single hybrid 彳 1- 彳 ... voltage 'is re-based on the power supply 11 After the power is turned on, a low-voltage signal is received, which is used to reset the unit. Rotation—Reset the signal to the long lock unit, the overvoltage protection device of M # 14, where the overvoltage early element is an overvoltage comparator, which is a comparison operation-the first-critical subtraction-supply voltage_signal, use this Progressive trigger unit. ^ 5. As described in item 1 above, the over-voltage signal f · Wei Danfu 1 is viewed, compared with the operation-the third critical 2 touch = pressure feedback sensing signal, used to output-the first The second protection signal reaches 7L as early as the progressive trigger. 6 · The overvoltage tilting device described in item # 1 of Patent # 15, the overvoltage signal acquisition and comparison unit includes: an overvoltage comparator, which compares a first critical signal with a supply voltage The sensing signal is used to output the first protection signal; the feedback ratio is a comparison operation_the third critical signal and the voltage feedback sensing signal is used to output the second protection signal; and the connection sheet 70, Connected to the over-voltage comparator, the feedback comparator, and the progressive trigger list 70, the first and second signals are transmitted to the progressive trigger unit. 7. The overvoltage tilting device described in item 1 of the patent application, the progressive triggering unit includes: a maintaining unit connected to the overvoltage signal acquisition and comparison unit and the oscillator, which receives the The protection signal and the clock signal are used to delay the state of the protection signal 21 ⑧ M278145 and output an up and down signal; and an up and down counting unit connected to the maintenance unit and the oscillator to receive the up and down signals and the The clock signal is used for counting operation, counts up according to the activation of the up and down signals, counts down according to the signal of the rainbow, and stops counting at the end of the down counting, and outputs the cut-off signal at the end of the up counting. 22 ⑧