TWI277854B - Switching controller having output power limitation and brownout protection - Google Patents

Abstract

A switching controller having output power limitation and brownout protection for a power supply is provided. The switching controller includes a limit-voltage generating unit to obtain a line-input voltage and generate a maximum power-limit voltage accordingly. The maximum power-limit voltage is compared with a current-sense signal for output power limitation. In addition, a PWM generating unit of the switching controller turns off a switching signal when the line-input voltage is lower than a hysteresis threshold voltage. Therefore, the power supply can be protected under brownout conditions.

Description

^277854 IX. Description of the invention: [Technical field of invention] A switching control woven device with output power off and low voltage protection, especially a switchable control device capable of J force rate output and low input power voltage protection. [Prior Art] In the power supply, the PWM switching technology is a conventional branching technology, which can be used to control the "steady adjustment of the input power; power. Various protections such as overvoltage and overcurrent protection Xianjian In the power supply, it is used to protect the power supply and peripheral circuits to avoid permanent damage. The power supply H is transferred to the ilj Shenguan Weitong in the short circuit protection. Refer to the figure - diagram, system A schematic diagram of a conventional power supply II circuit, wherein the switching controller Ui is composed of a force rate limiting comparator 53, an oscillating state 56, and a driving signal generating unit 54, and serves as a source of driving signals for the power supply 5, such as a pwm control integrated body. The circuit 3842, the PWM control integrated circuit 3842 has been widely used in commercial applications for the power supply. In the power supply 5, the input power supply V1N starts to maintain a capacitor Cst through a series of starting resistors RST. When charging is waited until the voltage Va on the sustain capacitor Cst reaches a starting voltage, the switching controller 仂 starts to operate to drive the entire power supply 5. The power supply 5 After the operation, the switching controller 仏 requires the supply voltage Vcc to be supplied by the auxiliary winding Να of the transformer 透过α through a rectifier Da to charge the holding capacitor CST. At this time, a detecting resistor Rs is connected in series to the power switch Qi It detects the transformer flowing through the power switch Τ! The primary side current Ip is used as the maximum output power of the power supply 5. The method is to detect the voltage on the resistor Rs (ie, a current sense § TL number Vcs Passing to the negative terminal of the power limit comparator 53 1277854. If the current sense signal vesA is at the set maximum power limit, for example, the voltage level, the nano-alkali transfer unit 54 will be simple (10) system_alkali> The turn-off, and will also limit the maximum output of the power supply ϋ 5. The energy ε stored on the transformer inductance is: -xLxl2 = ΡχΤ 2 ..........(1) Maximum output power P can be expressed as follows:

Ip :

Lp

• X t〇N ·····(2) -(3)

Lp 2 ViN2xt〇N2 _x |p _____

2xT 2 x Lp x T where Ip and Lp are respectively represented as the secondary side current and the secondary side inductance value (3) of the transformer Ti are the power _ (four) pass time 'Q峨 峨 Vpw guide 姊 a1; τ system is power on _ The switching period. It can be found from equation (3) that the output power ρ will change as the input dragon changes. When considering safety, the input supply voltage range of the power supply is determined by 264Vac. The output power limit at higher input supply voltages (264Vac) is usually higher than at lower input voltages (10) ac)__, while there are often several times the difference between high and healthy. Although the electric control wire can be used to control the circuit through the electric wire, the output power can be recorded. That is to say, when the electric field number I is higher than the maximum discriminating limit level V4, for example, VQ1V (Ip xRs g lv), the maximum on-time ^ will be limited at this time, and the primary side current of the power supply is limited. 1277854 Furthermore, the maximum output power is also affected by the drive signal generating unit 54. Transmission delay time td

With the first -B, street 帛: _, er (four) day _ into the input power supply under the wheel (four) report fresh and strange. The maximum power limit of the electric wire 5 is determined. The output of the wire is _ _ will be thin 峨 _ signal ^ and the continuous conduction time U is shorter _ signal ν_. Furthermore, in the case of the low-voltage wheel, the current sense is generated with a slower slope, and the drive signal ν_ with a continuous on-time (four) is longer. When the current sense signal Vcs is higher than the maximum power limit level % of the moment (^ X匕^ IV) 'The drive signal Vto of the drive signal generating unit 54 will be turned off after a transmission delay time of seven. Within the transmission _td, the scale _(4) is scaled, and Continue to transmit power. Therefore, the on-time field of 'real_峨峨Vral is equal to pure d. That is to say, when the input supply voltage is high, the actual on-time of the power switch Q1 is also increased, so the actual power is mixed. The VM reads high, and the incoming and outgoing calls are mixed with 5 output materials. It needs to be said _ Yes, whether it is at the higher and lower input power supply voltage, the transmission delay time in the same power supply. The size of the seven is the same. When the input power supply voltage is low, the actual on-time Wd of the power switch 3 will also increase. The actual power limit level VM, LV will be higher than the power limit of the input power supply voltage. Bit U is low. This leads to Wei !I 5 will produce several times the difference in output power under the very domain _ input voltage. The actual output power p is as follows... _ V2INx(t〇N +tp)2 ~2^ΓΰχΤ~ ... ................................................. ....(4) 1277854 Than the above formulas (3) and (4) of the rut, the propagation delay time td of the value L 内部 inside the ic will cause the excitation to be more than the theoretical value (VlN / Lp)*td Therefore, when the pressure roller is turned into the power supply, there will be a large force rate. The shaft transfer delay is usually between 250ns and 300ns _ circumference, and the higher operation is fresh, and the transmission is delayed. The impact is even more complicated. Therefore, the output of the class is a teacher, the axis _砸v„ will not affect the output power. [Summary of the Invention]

The present invention has a switching power control device with an output power limitation and a low electric castle protection. The main purpose of the control device is to dynamically output the power when the input power supply of the power supply is changed. In addition, if the input power supply voltage is too low, the output of the generator should be achieved, so that the protection of the low input power supply voltage can be achieved. 'The power supply will be stopped.' The invention uses a hysteresis comparison circuit to receive an equal proportion of the input power through the input resistor. The electric hysteresis comparison circuit compares the input power of the input power to the hysteresis threshold voltage. ^ lose & low private pressure magnetic _ 峨 'low voltage hysteresis tfl control drive signal to generate a single read drive 峨 ϋ 料 料 料 料 料 料 料 料 料 料 料 料 料 料 料 料 料 料 料 输 输 输 输 输 输 输 输 输 输 输 输 输 输 输 输 输 输The voltage generating unit receives an equal ratio of the input packet source voltage through the input resistor for outputting - the maximum discriminating limiting voltage. The power limiting comparator receives the maximum power limiting voltage and current sensing, and performs a comparison operation for the input. The power limit signal is used as the power limit of the power supply output. Furthermore, the present invention uses a driving signal generated by the power limiting comparator and the power switch to generate a single power supply (four) power limiting signal, which can output the driving signal to the power. Switch. By this, 1277854 when the power supply changes, the maximum power_voltage will change accordingly, which will cause the drive to generate an early 7L5 week full drive signal. The duty cycle is to limit the primary current of the power supply and reach the limit of the output power. In the case that the power supply voltage is too low, the hysteresis comparison circuit will perform the input voltage and the hysteresis threshold voltage value that are too low. The comparison operation generates a low voltage hysteresis signal for controlling the driving signal generating unit to stop driving the signal output as a low input power voltage protection. In order to enable the reviewing committee to further understand the features and technical contents of the present invention, please refer to the following related The detailed description of the present invention and the accompanying drawings are only for the purpose of illustration and description, and are not intended to limit the invention. [Embodiment] Referring to the third figure, it is a circuit diagram of a preferred embodiment of the present invention. The present invention is used in the power supply 6 to follow the change of the input power supply voltage %, thereby controlling the switching operation of a power switch Qi, including the hysteresis comparison circuit 6〇, the clamp voltage generating unit 62, Power limit comparison 1 63 and Hexun generating unit 64. Shiwei 6 () through the input resistor 艮 and r2 dust to take An equal ratio of the input power supply voltage Vin, and the ratio of the input power supply voltage Vw is compared with a hysteresis threshold voltage range value (the lower voltage threshold value V1 to the upper voltage threshold value Vh). Meanwhile, when the input is proportional The power supply voltage Vin is lower than the lower voltage threshold value vjf, and the hysteresis comparison circuit 60 outputs a low-level hysteresis signal ds of a low level, and outputs a low-level hysteresis signal Ds of a high level when the voltage upper limit value VH is exceeded. In order to form a signal hysteresis phenomenon, in the above description, the hysteresis threshold voltage range value is a voltage upper limit threshold value Vh with respect to the input power supply voltage of 90Vac to a voltage lower limit of 1,127,854 with respect to the input power supply voltage of 7〇Vac. Vj^. . . Referring to the third figure, the clamp voltage generating unit 62 is composed of -adding a fine connection - the voltage source Vr is formed by the input resistance Ri and the heart is obtained from the input power supply voltage ^ -V_ET ' The compensation voltage vOTFSET and the off-power Wei Vr are added to the adder (4), and then the fine-closed rate is turned off. The input power supply voltage is a variable value, such as a change from a high input supply voltage to a low input supply voltage. Therefore, the maximum discriminating voltage v bribe is also variable. Through the clamp voltage production, the electric fine system of the single-seat 70 62 can make the maximum power limit under the high-voltage power supply voltage. • The voltage Vl_v ' can obtain the maximum power limit voltage Vlmtlv under the low input power supply voltage, wherein Vlmt, lv is greater than The voltage level of vLMTHV. The power limit comparator 63 is connected to the clamp voltage generating unit 62, and receives the changed maximum power limit voltage VLMT, and compares the changed maximum power limit voltage problem with a current sense number Vcs. To output a variable power limit signal v〇c. φ 纟 refers to the second figure 'the driving signal generating unit 64 is connected to the hysteresis comparison circuit 6 〇, the power limit comparison 1 63, the power switch Q and the feedback end of the power supply, receiving the low voltage hysteresis The signal DS and the power limit signal v〇c are used to output a driving signal ¥_ to the power switch Qi. The driving signal generating unit 64 includes a PWM comparator 642, a logic circuit 644, a flip-flop 646 and an oscillator 648. The PWM comparator 642 is connected to the power limiting comparator 63 and the feedback terminal of the power supply for receiving a voltage feedback signal vFB and the current sensing signal Vcs, and simultaneously comparing and calculating the sfL number of the electric castle feedback Vfb and $Hai current sensing number Vcs for outputting a modulated output 1278854

Vp〇. The circuit relay VP0 is transferred to the logic circuit 644 of the power limit comparator 63 output circuit 644 to obtain the power switch ν. . Lin Hsin lost the signal Vp〇, and the implementation and the '_之赖' continued - reset 峨 ^. The flip-flop 646 is connected to the hysteresis comparison circuit 6〇, the logic circuit 644, the undulator 648, and the power switch Q1, and receives the low-voltage hysteresis signal ds, the reset signal v and an oscillation signal. CLK '駄 output noise 峨νρ·_ God switch ^. The brother type 4 positive and negative benefit 646 is a D-type flip-flop, and a reset terminal (8) is connected to the output end of the logic circuit 644, and receives the reset signal %, and the clock-end ((5) is connected to the surface. Tree_slot_CLK, the output end of the input terminal 〇 滞 comparison circuit 6 用以 is used to receive the 峨 hysteresis signal ds, the output paste is connected to the power switch Q, and the control end is used to output __ No. 碌 盥 CLK CLK control ^,, Q 八... eight w 峒 (9) to obtain the low voltage hysteresis signal 'Asian touch (four) (Q), „, Na Wei =- type flip-flop reset, Over power - ^ enough Norman sacrifice type TM due to the power limit of the power limit chain v Conghe rely on V (four) _ _ = = _3 output number % of the output to reach the output power limit. Again, = 46 Used to adjust the drive signal control forward and reverse device 646 round or 1 magnetic minus DS system can be used in conjunction with the humiliation - 嶋 her wheel material input line l277854 power supply under the power limit level « schematic. The clamp cake produced by 2 “The source voltage is low with the power source to produce the largest identification dragon”

Gold v, VLMT, HV _ ν ' and the current sense signal vcs obtained by the detection resistor Rs are respectively Vcshv and the pin current sensing signals Vcshv, Vcslv will pass through the power limit comparator (4) to take the high power shut cage Vl_v, ^ sand into the 槪 comparison operation, and the guidance office is W and W drive 峨 Vp side, take, VpwM, Lv. In the above description, if you consider the delay generated by the switching control, the high-speed input The actual power-on voltage of the human power supply voltage and the low input power supply voltage are respectively Swtd and w+td. From the above, it can be seen that the voltage supply function of the clamp voltage generating unit 62 allows the power supply 6 to become the largest in Gao Guanjian. _ _ V V, as the power supply 6 output power compensation Gan ',, the knife half complement, its continuous maximum power limit voltage VLMT is the same 'and can get stable and the same output power P. The fifth figure of the first picture is the waveform diagram of the hysteresis comparison circuit of the present invention. At time t1 to t3, the input power supply voltage VIN is smaller than the upper voltage limit value VH. At this time, the input power supply voltage VIN is transmitted. The magnetic The comparison circuit 6〇 starts the hysteresis comparison operation, and at the time ^, the input «light W is the lower limit value of the voltage threshold value. At this time, the sir comparison circuit 6 〇 outputs the low-level hysteresis signal of the low level, and the rib control The flip-flop _ stops the driving of the VPWM, and in the other day (four) (four), the input power voltage (four) depends on the upper limit threshold value VH. At this time, the magnetic flat ratio circuit 6G outputs the low-voltage hysteresis signal ds of the high level. In order to control the output of the forward and reverse H 646 recovery drive signal #uV_. This month has eight input iii power and low voltage protection switching control weaving, in the power supply for 12 1277854 When _, Lin's output is _, if the input power is too low, the output of the power supply will be stopped, so that the protection of the low input power supply can be achieved. However, as described above, it is only the present invention. The invention is not limited to the details of the present invention, and is not intended to limit the scope of the invention, and all the scope of the invention should be determined by the following claims. The essence of the patent application scope of the present invention ^ Similar variations of the embodiments are to be included in the scope of the present invention cuff, any person skilled in the art in the present invention ^ the art, and can easily think of variations or modifications encompassed Jieke patentable scope of the following case.

13 1277854 [Simple diagram of the diagram] The first diagram is a schematic diagram of a conventional power supply circuit; the second diagram is the transmission delay time caused by the high and low voltage input power - the vertical θ ·, the output power limit level difference is shown in the present invention The circuit diagram of the preferred embodiment; the fourth figure is a schematic diagram of the difference of the output power limit level under the high and low voltage input power caused by the transmission delay time of the present invention;

The fifth figure is a waveform diagram of the hysteresis comparison circuit of the present invention. [Main component symbol description]

5 power supply 56 oscillator 62 clamp voltage generating unit 62 〇 adder 64 drive signal generating unit 642 PWM comparator 646 forward and reverse 仏 switching controller Q1 power switch V 〇 FFSET compensation voltage Voc power limit signal Vcs current sensing Signal CLK oscillation signal 53 power limit comparator 6 power supply 648 oscillator RsT start resistor Da rectifier % limit voltage source Vrst reset signal 54 drive signal generating unit 60 hysteresis comparison circuit 63 power limit comparator 644 logic circuit

Cst maintenance capacitor Transformer V»Max power limit voltage Vpo modulation output signal DS low voltage hysteresis signal V compensation drive signal 14

Claims (1)

1277854 X. Patent application scope: • A switching control relay with output Shen Guan and Xiao Long Lai, used in a electrotherapy supplier, followed by the change of the input power voltage, and then control and adjustment - power switch A driving signal includes: - a hysteresis comparison circuit, which receives the input voltage of the #__ and the hysteresis threshold voltage range value, and after the comparison operation, outputs a low voltage hysteresis signal; the stomach clamps the voltage The material is generated by using a limiting voltage source and the varying input power voltage for outputting a maximum power limiting voltage; - a power limit of n is connected to the clamping voltage generating unit and the power supply The sensing end 'receives the maximum discrimination and the sensation, and compares the maximum power limiting voltage with the current sensing signal for outputting a power limiting signal, and driving the carrier unit __物_ bribe, face-to-face comparison circuit, the power supply-return terminal, the power supply to find the sensing end and the power switch, the system = _ _, w, - __ fine current sense, number To output the drive signal to the power switch. m special wealth 丨 述 具有 具有 辨 辨 辨 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她 她After the power supply voltage and the limit, the maximum power limit voltage is taken out. 3. For example, the control device, wherein the driving signal generating unit includes: - a PWM comparator connected to the feedback end of the power supply and the sense The measuring end receives the voltage feedback and the cake_signal, the root view_long cake gift signal and the 5 hai sensing δίΐ number, for outputting a modulated output signal; the device 'receives the logic circuit, and connects In the discriminating limit, the power limiting signal and the modulated output signal are used to output a reset signal; and the flip-flop is connected to the hysteresis comparator circuit and connected to the reset terminal. The a logic circuit, a clock terminal connected to an oscillator, and a receiving the low voltage hysteresis signal, the reset signal, and an output terminal connected to the power switch, the vibration disk nickname for outputting the driving signal to the power switch. 4. The switching control device with output discrimination and low tilt as described in the third paragraph of the patent application, wherein the flip-flop can be selected from a D-type flip-flop, an SR-type flip-flop or a jk-type positive and negative One of the group combinations. 5.- Switching control device with output power limitation, used in the power supply, with and according to the change of the input power supply voltage, and then control and adjust one of the driving signals of a power switch, including: ...L The Xia generation unit uses the _Longyuan to communicate with the changed input power voltage for outputting a maximum power limit voltage; a power limit is substantially ϋ connected to the clamp voltage generating unit and the power supply A sensing end is 'receiving the maximum power and the Wei pressure and the electric measurement signal, and the maximum power is limited to the dragon without a butterfly _ fine _ petals, ^ persuasion - pants limit signal 16 1277854; and - drive signal generating unit Connected to the power limit comparator, the return end of the power supply, the sensing end of the power supply, and the power switch, receiving the power limit λ旒, a voltage feedback signal, and the current sensing a signal for outputting the driving signal to the power switch; thereby, when the input power voltage changes, the maximum power limiting voltage changes, and the power limiting comparator is further adjusted The power limitation of the signal, and adjusts the drive control signal generating means in the output signal of the crane for the post to the primary side of the power supply current of the ship. 6. The switching control relay with output power limitation as described in claim 5, further comprising a hysteresis comparison circuit for receiving the input power supply voltage and the hysteresis threshold voltage range After comparison, a low voltage hysteresis signal is output or cut off. 7. The switching control device with output power limitation according to claim 5, wherein the clamp voltage generating unit is composed of an -additive connection- Guanxian source, and the adder will change the input power source. After the addition of the voltage source is performed, the maximum power limit voltage is output. 8. The switching control device with output power limitation according to item 5 of the patent application scope, wherein the driving signal generating unit comprises: - a comparison comparison II, the feedback of the feedback terminal connected to the occupational power supply Receiving the voltage feedback signal and the current sensing signal, and calculating the voltage feedback signal and the current sensing signal according to the comparison to output a modulated output signal; 17 1277854 a logic circuit connected to the power The limiting comparator and the PWM comparator receive the power limiting signal and the modulated output signal for outputting a reset signal; and a positive and negative benefit, an input terminal is connected to the hysteresis comparison circuit and a reset The terminal is connected to the logic circuit, the clock terminal is connected to the oscillator, and an output terminal is connected to the power switch, and the low voltage hysteresis, the reset signal and the vibration signal are received to output the driver. Signal to the power switch. 9. The switching control set with output power limitation as described in claim 8 of the patent application, the flip-flop device may be selected from the group consisting of a D-type flip-flop, an SR-type flip-flop or a JK-type flip-flop. Group combination - 〇