TW493317B - Switching-mode instrumentation power supply capable of providing outputs of constant voltage and constant current - Google Patents

Abstract

A kind of switching-mode instrumentation power supply (SMIPS) having zero-voltage-switching pulse-width modulation (ZVS-PWM) technique is disclosed in the present invention. The ZVS-PWM SMIPS is capable of providing outputs of constant voltage or constant current under the condition that output voltage/current is adjustable. In the control method, the purpose stated above is obtained by using voltage-adjust control (VAC) apparatus and current-limit control (CLC) apparatus. In addition, linear voltage regulator (LVR) with high efficiency is used to regulate voltage.

Description

J 丄 / J 丄 / Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 V. Description of the invention 0) ~-~ The present invention relates to a type of switching power supply for instruments, which can provide voltage output or current output And ensure the system's low power loss and efficient power supply output. Generally, the DUT uses the switching power supply II (switching power s ^ P =) to provide the required power. Traditionally provides the power supply required for the DUT. 1 = Use a linear power supply. Linear power supply 11 is often used in power supplies for instruments that can provide high voltage or constant current, and provides low ripple noise, low electromagnetic interference (10w emi), good regulation, And easy control. Although the linear power supply has been widely accepted by the general user in the market, it still has some disadvantages such as: large power loss and low power efficiency. Furthermore, due to the large size and efficiency of the power supply for instruments, it has become an inevitable trend to use switching technology (switching-mode teChmqUe) to make power supplies for instruments, and to improve power density and power efficiency. . As shown in Figure 1, the traditional parent-type power supply uses the circuit's on and off loops to repeatedly change the DC voltage after the input voltage is rectified and filtered, and the results are filtered. Get a fixed output voltage. Generally speaking, the parent-type power supply is a high-frequency electronic device, and its operating frequency is currently mostly between 20KΗζ to 200KΗζ. In the system circuit, its power switch, such as a transistor or metal-oxide-semiconductor field-effect transistor (MOSFET), will work in the saturation and cutoff regions. The traditional linear power supply usually uses a transistor that works in the linear region, and uses it as a rheostat to adjust the unstable input voltage. — — — — J — — — — — — — 1111. (Please read the notes on the back before filling out this page) Order · · --Line · 3

This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 Gongfa 493317 A7 B7 printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the invention (2) In this type of circuit, the passive components must bear The current that changes with the load, once the input voltage changes or the load suddenly increases, the power consumed by the passive components also changes or increases. Therefore, the power lost in the entire system also increases, and the efficiency decreases. However, the switching power supply does not fully work in the linear region. Therefore, even if the input voltage range varies widely and the load varies greatly, it can still obtain higher efficiency than the linear power supply. Nowadays, it is widely used. Switching technologies are pulse-width modulation (PWM) and spectral resonance. However, because of high exchange losses and serious electromagnetic interference, the use of PWM conversion is restricted, and PWM conversion cannot be applied. In switching mode instrumentation power supply (SMIPS). The concept of spectral vibration is applied to power conversion, resulting in zero-current-switching (ZCS) and zero-voltage-switching (ZVS) in power switching; and for high power density and high efficiency The development of low-noise power supplies guides a clear path. The resonance conversion technologies that are widely used today include series-resonance, parallel-resonance, and quasi-resonance (QRC) ), Where qrc conversion has high voltage / current stress, and thus limits its practical use, QRC conversion is not suitable for use with other general converters. Today, the use of ZVS-PWM technology is to increase power density while maintaining A better strategy for high efficiency; because ZVS-PWM technology combines the advantages of previous PWM low conduction loss and zero voltage / current exchange of QRC in power exchange. At present, various ZVS-PWM prototypes have been published on the market. Provides high reliability and efficiency

(Please read the precautions on the back before filling out this page) Binding-Line-493317 A7 Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs and Consumer Affairs Co. V. The power supply of invention description (3) is used in various applications. In view of this, the present invention proposes a SMIPS module that incorporates the ZVS_pwM technology and uses a full-bridge converter (full-bridge, FB). [The SMIPS proposed by the present invention is capable of providing constant-voltage (CV) and constant-current (cc) outputs with adjustable output voltage / current. The control method is achieved by using a loop of a voltage adjustable control device (v〇hage_adjust control 'VAC) and a current limit control device (current) imit c0mr〇1 (CLC). At the output end, a high-efficiency linear voltage regulator (11-shaped rainbow voltage regulator, LVR) is used for voltage regulation. According to the above-mentioned purpose, the present invention proposes a switching power supply for an instrument, which can provide a constant voltage output or a constant current. The output includes: a full-bridge converter device 100, which converts a relatively south DC voltage into a relatively low DC voltage, and the full-bridge converter device includes a feedback voltage input terminal; (2) a linear voltage The adjusting device 102 responds to the relatively low DC voltage to convert it into the output voltage of the switching power supply. The linear voltage adjusting device provides a control voltage output. The linear voltage adjusting device includes: The two-stage changeover switch 122 is used to switch between a first input signal and a second input signal; a linear voltage is II2 'to properly adjust the changing action of the output load current and generate the control voltage, ( 3) -Voltage controllable relay 1 (M, using a relay relay power supply to operate in a constant voltage panel mode. It should be used to output the first-input signal to the two-stage switching off; ⑷- current limit control device 106, which is used to control the switching power supply to operate the ballast control device in the constant current mode. The output voltage of the switching power supply responds with the wheel = the second input signal to the two-stage switching off; (5) _ amplifier, the linear ^ K Zhang listens to X 297 mm)- ------------ I--Equipment ---- (Please read the precautions on the back before filling in this page) * 101 、 · Line · A7

493317 V. Description of the invention () The control voltage provided by the regulating device is compared with a sense-inductive mu A electric relay, with wheel-out-error electric 12, _qianzhangqi provided by _ «, light-wheel-out- The training voltage and (7) _zero voltage switching pulse width modulator U4 'are used to connect * the light-age voltage provided by the optical coupling rider to output-feedback voltage to the feedback of the full-bridge converter. The voltage input terminal is used to increase power density and maintain high power efficiency. The step-by-step power supply for the power supply further-includes-a suitable reference voltage generator 108, to provide the reference voltage required by the amplifier. In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below in conjunction with the accompanying drawings for detailed description as follows: Brief description of the drawings: FIG. 1 is a conventional Switching power supply; Figure 2a is a block diagram of a switching instrument power supply (SMIPS) with zero voltage switching pulse width modulation (ZVS_PWM) technology; Figure 2b is a pulse width adjusting with zero voltage switching Simplified circuit diagram of ZVS-PWM technology switching power supply (SMIPS); Figure 2c shows the main power stage of the ZVS-PWM-FB converter; The figure shows the output characteristics of SMIPS in constant voltage and constant current mode; Figure 4 is a block diagram of the SMIPS system control architecture of the present invention; Figure 5a is a block diagram of SMIPS current adjustable control in constant current mode; Figure 5b Figure 5c shows the small signal equivalent model of SMIPS in constant current mode. Figure 5c shows the mathematical model of SMIPS in constant current mode. This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) I --- ----------- Install -------- Order-- ------- line (Please read the notes on the back before filling this page) Printed by the Employees 'Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Printed by 493317 V. Invention Description (5) Figure 6a is a block diagram of adjustable voltage control of SMIPS in constant voltage mode; Figure 6b is a mathematical model of SMIPS in constant voltage mode; Figure 7 is the waveform diagram of Ip,% and Vab in ZVS-PWM converter; Figure 8 is the ZVS-PWM SMIPS physical circuit diagram; Figure 9a is the current and voltage waveform diagram of the main current and voltage IB when V〇 == 10 / I〇 = 10A; Figure 9b is V〇 = 30 / I〇 = 4.5A daily current, current and voltage waveforms of main current ^ and voltage%; Figure 10 is a schematic diagram of power efficiency versus load current at a specific output power, and Figure 为 is a rotation output under constant voltage mode Schematic diagram of voltage regulation (V0 = 50V); Figure ub is a schematic diagram of output current regulation in constant current mode (I0 = 10A). Explanation of symbols: 100 to full bridge converter device; 102 to linear voltage regulator device; 112 to linear voltage regulator; 122 to two-stage switch; 104 to voltage adjustable control device; 106 to current limit control device; 108 to Adaptive reference voltage follower; 110 ~ amplifier; This paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 public love) One J — — — — — — · 11 (Please read the note on the back first? Matters (Fill in this page again)--· Line-493317 A7

Printed by Mao Ming, the Consumer Property Cooperative of the Bureau of Intellectual Property, Ministry of Economic Affairs, the block diagram and simplified circuit diagram of the power supply (sMips) for switching instruments with zero voltage switching pulse width modulation (zvs · P WM) technology As shown in Figures 2 and 2b, the second is the zero-voltage switching pulse width full bridge (ZVS_PWM_FB) converter. It is used as the main power stage of the power supply for switching instruments. Since it is impossible to operate the amplifiers in ㈣ and the current loop at the same time, for any load resistance, the power supply ^ 疋 畲 as a constant voltage supply is used as a constant current supply. However, the present invention will automatically switch the power supply for the switching instrument as a constant power source or a fixed power source. Its operation principle is detailed later. -In the two operation modes of constant voltage and constant current, according to the relationship between the output voltage setting and the ratio of the output current setting and the output load impedance, the present invention automatically switches the output operation mode. Figure 3 illustrates the output characteristics of an ideal constant current and constant current supply. The output load is open (―), the output current ㈣ and V〇 VSET, where VSET is the control voltage for the front panel setting. When there is a load at the terminal, the output current increases, while the output voltage remains fixed;: 3 The output H point represents a typical more voltage operating point. Furthermore, reduce the load resistance Z and increase the output current, and the output voltage will remain fixed until the output current reaches' where ISET is the control current set by the front panel; in this case, the power supply automatically = # The operation mode is switched from a constant voltage source to Constant current source. If the load value continues to decrease, the output voltage will begin to decrease. The output current remains fixed, as shown in Figure 3.

B (Please read the notes on the back before filling in this -1) • -Binding & Thread. The paper size is based on € 5¾ standard (CNS) A4 size (210 X 297 ^ W) 493317 A7 Employees of Intellectual Property Bureau, Ministry of Economic Affairs Printed by the Consumer Cooperative 5. The invention description (7) point represents a typical constant current operating point. If you continue to reduce the load resistance value, the output voltage will continue to drop, the output current will remain fixed, and the output will be short-circuited at last, I0 = ISET, V〇 = o. Conversely, if the output load is gradually changed from the output short circuit to the open circuit, the operating track of the constant voltage and constant current power supply in Figure 3 will be reversely displaced. The full range of protection under any overload condition is obvious in the design principle of the voltage and constant current power supply, because the output overload caused by all load conditions is in the operating trace of Figure 3. Whether it is constant voltage operation or constant current operation, the proper ^ and U selection can ensure the best protection of the load device 'just like the full range protection of the power supply. The slope of the dotted line passing through the origin is proportional to the load impedance at the output of the power supply. The critical value of the load impedance is defined as, Rc ~ (1) 1 set The pen pressure and the regulating current of the set allow 3 o'clock running, and the impedance is set to the desired value from 0 ~ ⑺. For example, if RL > RC, the power supply operates as a voltage source in constant voltage mode; otherwise, if rl < rc, the power supply operates in constant current mode. Fig. 4 is a block diagram of the system control architecture of the switching power supply for an instrument of the present invention. The ZVS-PWM controller 114 is controlled by VAC104 and CLC106 to maintain the output of the power supply in constant voltage mode or constant current mode. The LVR112 with high efficiency is set at the output for voltage regulation. The LVR112 is an enhanced MOSFET. Due to the adaptive reference follower (ARF) 108, the MOSFET has an adaptively adjustable drain-source voltage. The ^^ 108 provides the current sensing voltage VR3 to follow the voltage Vs to maintain the gate electrode 9 ^ The paper size is applicable to the Chinese Standard (CNS) A4 specification (210 X 297 male f '' (Please First read the phonetic on the back? Matters and then fill out this page) Binding · ί Thread. 493317 A7 V. Description of the invention (8)-The voltage of the source is within an acceptable range, so that during the voltage adjustment, = = source-source is provided Voltage vDS. This means that the VDS will decrease with the load out of the wheel: while in steady state W because the larger the 10, the larger the VSA ', the larger VR3 is, so the larger the vs is, the smaller the vDS is. 2 =, the problem of high linear consumption. Among them, Vs is based on the voltage sensed by the current of circle 12; and VR3 is based on the instantaneous induced current and the voltage value of the negative reference voltage source (here -10V). , ~ —-10 and + 仏. And 6 i? 5 + Re About the current limit control principle of the present invention in constant current mode, the principle of adjustable voltage control in constant voltage mode, mathematical analysis of SMIPS, and 2 ZVS_PWM actual The circuit and measurement results are described in detail below. I. Current limit control in constant current mode Referring to Figure 4, the differential amplifier Amp detects the output current from the current sensing resistor & when the output current is a maximum value, the maximum voltage of the output terminal vSA is 10V. At this time, the current limit reference voltage of VSA and EA2 For comparison, the current limit reference voltage Yu ranges from 0 to 10V. When Vsa > vR2, which means that when the output current exceeds the set output current value, v = Vg; the voltage value of the output terminal of EA2 becomes larger than the original value. It is also low, thus reducing the drive of the regulator. Limiting the output current until VSA = VR2, the precise current regulation rate can be achieved. Using this mechanism of the invention, the output current will linearly track the current adjustable controller from zero to Maximum output current. If the output current drops to the current limit setting of 10 This paper size applies to China National Standard (CNS) A4 specifications ⑵G x 297 public hair) ------ I ------- installation-( Please read the notes on the back before filling out this page) LT · Line · Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 493317 A7 -----------________ 5. At the time of the invention description (9), High level, at this time the VAC104 circuit will be As to control the output voltage mode. ---------------- ^ — (Please read the note on the back? Matters before filling out this page} Figure 5a shows the current adjustable in the constant current mode of Figure 4 Control block diagram, where rl < rc and Vg are coupled to the output switching point 2 of CLC106. When the induced current flows through G2 to change vs, and via CLC106 to obtain the accompanying voltage VRS, Vg is within the selected constant voltage range In order to maintain a constant current at the output terminal, a constant current output with adjustable current can be obtained according to the load change. Figures 5b and 5C are shown in Figure 5a respectively. In constant current mode, the small signal equivalent model and mathematics Model.-Line 1. Refer to Figure 4 for the principle of adjustable voltage control in constant voltage mode. When operating in constant voltage mode,% is a high level potential and Vv = Vg, which causes CLC106 to not operate and VAC104 to operate. When the wheel-out lightning pressure rises, because the voltage of the negative input terminal of EA1 is higher than the positive input terminal, the voltages of Vv and Vg drop (at this time vv = Vg), so that the output current flowing through the subsequent stage LVR112 is reduced, so the output The voltage will be adjusted to the output voltage proportional to the reference voltage VR1. R3 and R4 constitute The voltage division network of the output voltage causes the output voltage to be the maximum when the maximum VR1 = 10V. In this way, the output voltage linearly tracks the output voltage of VAC 104 from zero to the maximum. Printed by Figure 6a of the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs Shown in Figure 4 is a block diagram of the adjustable voltage control in the constant voltage mode, where RL> RC, and Vg is coupled to the output switching point 1 of VAC104. When the induced current flows through G2 to change Vs, and obtain CLC106 to obtain When the accompanying voltage VRS, Vg is an optional reference voltage from VAC104 to maintain a constant voltage at the output, so a constant voltage output with adjustable voltage can be obtained according to the load change. Figure 6b is a mathematical model in constant voltage mode. 11 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) A7

V. Description of the invention (10) 1. Mathematical analysis of SMIPS ZVS_PWM in Fig. 2b is shown in Fig. 7. In the vehicle: the waveform diagram of the 1P, V ^ Vab, and the valid duty cycle Deff in the high cycle is only between time ti and h. Deff = Z) — AD AD = ^ ~ h_ h〇 ~ y〇 (2) (3) 4fsL0 ID)… D in the middle is the duty cycle of the PWM controller, △ D is the Ji and duty cycle reduced due to zvs' fs is the switching frequency, n is the number of turns ratio, L0 is the crossing current, and LR is the courtesy inductance. If the effective duty cycle disturbance S in Smip is considered, it can be expressed by the following formula: ~~ ^ eff + ^ eff (4), according to the analysis of the small signal and circuit model, and because the input voltage vin is set to $, ignore the input voltage The effect element is adjusted for the work cycle, so the effective work cycle disturbance amount in De // can be simplified as follows: ------ I ------- install-(Please read the precautions on the back first (Fill in this page again) deff = d + dt and di Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs

Rd ^ n2fsLR (5) (6) ⑺ Among them is due to the change of L, i is a small change of D, and L 疋 is caused by the change of Vm. From Figure 5b, the output filter inductor current can be obtained. The transfer function of the effective duty cycle is 7 cs2 + (is + l 1 '一 = ____ ^ 卞 ΜΛ 卞 丄 deff " L〇xcs3A ^ dL0] s2 + (b + L〇 ) s ^ {RL + Rs + r〇s] (8); line · 12 This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) 493317 A7 B7 V. Description of invention (11) where a = Resrx [RlResr2 + i ^ esrl + RL \ RS ^ RDS) \: 0, C〇2 (9) b = (RL ^ Rs + Rds) ResrlC0, + [RLResr2 + (Resrl + rl \ rs + R〇s 〇2 (10) C = (Resrl (Resr2 ^ RLkRLResr2 + + ^ + ^) JC〇1C〇2 (11) and d = (Resrl + RL + Rs + Rds) C〇1 + (Resr2 + Rl) ^ o2 (12 From Equation 5 to Equation 8, the transfer function of the filter inductor current to the duty cycle can be obtained as

Ga (s) = l ^-= nVin—3—— __C52 + ds + l _ ds L〇C + s2Ka + dl ^ + l ^ cl + sib + L0 + + + rds + Rd) can be obtained from Figure 5b Impedance (13) (Please read note 3 on the back before filling out this page) ζ / (5) = τ ^-= 5, ζό + < lLo 'scZ + Resrl -01

SC

-+ R esr2 Therefore, the power stage gain in 疋 current mode is cs2 + ds + lz in — (14) s L〇C + dL0) ^ Rdc] + s (b + L0 + Rdd) ^ (RL + Rs + RDS + Rd) ^ ^ x SLcr1 + Resrl V this 0 / SCt

-+ JR 02 esr2-equipment -------- order --------- line

The consumer function cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs printed the transfer function Gb (s) of sensing current to output inductor current as Gij (s) = ^-= ---- il / s ^ ol + ^ esrl) __ k0 v / sCol + ^ eSrl) + | (V5C, o7 + Resr2) + + RDS \ The transfer function F (s) of the sensing current to the secondary output voltage is js__ ^ F (i) = t = txr = WGi (5) The gain A (s) of the output voltage to the sensed current is 4 ^) = ^ =

Rb / R〇 ^] + sRaC 13 This paper size is applicable to China National Standard (CNS) A4 (210 χ 297 mm) (16) (17) (18) 493317 A7 B7 Employees ’Cooperatives, Intellectual Property Bureau, Ministry of Economic Affairs Print 5. Description of the invention (12) The gain Gd (S) of the optocoupler is ^ eaS Rf,] + sRcCc, where CRT is the current transfer ratio of the optocoupler, and the gain K4 of the PWM is d 1 (19) κ4 (20 ) Among them, the peak voltage amplifier of the sawtooth wave vD, the gain of the ugly 4 is ^ ea4 R!] 3 K3 (21) R112 According to Equation 20 and Equations 6 to 17, the duty cycle of the output voltage of the optocoupler can be obtained. K

Kj K2 ^ w ^ ea4

^ ea4 Fire ΕΑ! gain is ι _ SmRDS

1 + gmRDS RDS + RS 7 + gmRf) s are defined here

Gg (s)-h < ^ ea3 k3k4 113 VD R112: Gci (s) xKxGpi (s) xF (s) and the current open-loop transfer function is to use a mathematical tool to simulate ThpJS. The current compensator can be obtained. 0 μ = ^ = Rs / R6 V. I + sR5C3, so the required loop transfer function T ^ peJS) is eight "= G / co (Small G >) x (feet 2 + 4 * 0) (22) (23) (24) (25) (26) (27) (28) ---------------- install -------- order --------- line (please read the back first Note: Please fill in this page again.) 14 This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) (29) 493317 A7. 5. Description of the invention (13) where the current compensator is the entire required loop current gain. Τ person price 丄 = _K] G + v,} + GIc〇Gg [K2 + A (s)) can be obtained from Figure 6 〇h (s) ~ ^ r = Ri-? F〇2 ^ esr2 + ^ is sCo2 (RL + Ksf2) +! Let t = 〇, open loop voltage gain is ^ v, open (s) = ^ l (s) x Gh (s) can be obtained by Matlab simulation, R3! + sCj (Rj + R2 ) Therefore, the closed-loop transfer function of the voltage loop is closed (^) ~ ^ vco (^) X ^ / (^) x Gh IV. ZVS_PWM actual circuit and measurement results The actual circuit embodiment sets the specifications as: 0 ~ 50V and Vin = 380 ± 20Vdc. At the same time choose the work ((30) (31) (32) (33) (34) --------- install ·-(Please read the precautions on the back before filling this page) Order · Ministry of Economic Affairs wisdom Printed by the Consumer Cooperative of the Property Bureau 〇 ~ 10A, 〇35, the number of turns N = Ns / Np == 5/23 == 〇217, ^, the period is for people and main current Ip, max = I〇, maxN = 2.17A. Because the critical main current is a function of Lr at the same time, ^ can be repeated to check the results. First, make ZVS occur when the output current is higher than I0, critiCai = 4.6A, and the required main current is ip criticai = NxI〇 ， Criticai = i · 〇α ， resonance inductance Lr is LR = 80 // LR from LR = CsVin2 / IP-s2. Operating frequency fs = 100KHz, equivalent resonance capacitance CR = 654pF, and output filter inductance L〇 = 30 / / Η, the current sensing resistance Rs = 20m ^ a.

V 15 This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 493317 A7 B7 V. Description of the invention () 14 UC3879 is used here as ZVS-PWM controller 114, with low RDS ON = 55mri The enhanced MOSFET IRF150 is used as LVR112, and the circuit diagram is shown in Figure 8. Figure 9 shows the current and voltage waveforms of the main current Ip and the transition voltage VAB. It can be clearly seen from the figure that the main current is very close to the prediction. Figure 10 shows the power distribution to a single AC / DC module when the output voltages are 10V, 20V, and 30V, respectively, and is expressed in terms of power efficiency versus load current. Figure 11 shows that the output regulation is maintained within ± 0.2%. Although the present invention is disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and retouches without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application. (Please read the precautions on the back before filling out this page) Cap, ττ Printed by the Staff Consumer Cooperative of the Central Bureau of Standards, Ministry of Economic Affairs This paper is sized for the Chinese National Standard (CNS) A4 (210X297 mm)

Claims (1)

丄 / A8B8C8D8 VI. Patent application scope L-type switching power supply for instruments, which can provide constant voltage output or constant current output, including:-Full-bridge conversion n device 'Converts-relatively high DC voltage to a relatively low DC voltage The full-bridge converter includes a feedback voltage input terminal; a linear voltage adjustment device that responds to the relatively low DC voltage to convert the wheel-out voltage of the switching power supply, the linear voltage adjustment The device also provides a control voltage output. The linear voltage regulating device includes: a two-stage switch for switching between the first input signal and the second input signal; ^ a linear voltage regulator, Adjust the output load current appropriately and generate the control voltage; 6 A voltage adjustable control device is used to control the switching power supply to operate in the 疋 voltage mode, and the voltage adjustable control device responds to the switching The output voltage of the power supply to respond to output the first input signal to the two-stage switch;-current limit control The setting is used to control the switching power supply to operate in a constant current mode. The current limit control device responds to the output voltage of the switching snow source to output the second input signal to the two-stage power supply. A switch; an amplifier that compares the control voltage provided by the linear voltage regulator with a reference voltage to output an error voltage; an optocoupler that accepts the error voltage provided by the amplifier The light consumptive mode outputs a light Iz combined voltage, and a zero-voltage switching pulse width modulation converter to accept the optocoupler (please read the note on the back? Matters before filling this page). Installation --- -Order --------- line! Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 17 A8 B8 C8 D8 VI. # Following, the optical coupling voltage is deducted by the hall, and the feedback voltage is output to the full bridge transfer voltage. At the input end, "the power supply density is increased and the power supply is maintained. The switching power supply device described in item 1 of the patent scope is included, an adaptive reference voltage generator is provided to provide this amplifier. Reference voltage: The switching power supply described in item 1 of the patent scope declared by the poor, and / or a linear voltage regulator as an enhanced MOSFET. ▲ 4 · As described in item 丄 of the patent scope Switching power supply, /, 2 and 4 switch type switches are a diode. —5. The switching power supply as described in item 2 of the patent application scope, wherein the enhanced MQSFET operates in a linear ------.---.---------- Order ---------- Line 丨 (Please read the notes on the back before filling (This page) Printed by the Consumers' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs This paper is sized to the Chinese National Standard (CNS) A4 (210 X 297 mm)