TWM453303U - Half bridge dual output LLC series resonant converter - Google Patents

Description

Half-bridge dual output LLC series resonant converter

This creation relates to an LLC series resonant converter for a switched power supply, especially a half bridge dual output LLC series resonant converter.

In recent years, the technology of the switching power supply has become more and more sophisticated, and most of the switching power supply adopts a two-stage circuit architecture. Please refer to the first figure, which is a schematic diagram of a conventional switched power supply. As shown in the first figure, the conventional switched power supply 1' includes: a rectifying unit 11' and a power factor correcting unit 12 ', a DC/DC conversion unit 13', an output unit 14', a PFC control unit 15', and a converter control unit 16'. The first stage power factor correction unit 12' is typically a boost converter that boosts the rectified mains input voltage to 390V and causes the input current to be in phase with the input voltage. So that the power factor is close to 1.0. The second stage DC/DC conversion unit 13' converts the voltage of 390V into the voltage value required for the output unit 14' (i.e., the load terminal).

The hard switching method used in the early power supply is easy to cause switching loss when the power switch is switched, and the switching loss is increased with the increase of the switching frequency, which leads to low conversion efficiency and low heat dissipation of the circuit. Problems such as electromagnetic interference. Therefore, in order to solve The problem derived from hard handoff, the technique of flexible handoff is proposed. The flexible switching system adds a resonant inductor and a resonant capacitor to form a resonator. Thus, when the power switch is switched, the voltage across the power switch is converted into a sinusoidal voltage or current via the resonator to achieve zero voltage switching (zero voltage). Switching) or the purpose of zero current switching. This switching technology not only reduces switching losses, but also enables the circuit to be miniaturized.

At present, resonators are mainly divided into Series Resonant Converter (SRC), Parallel Resonant Converter (PRC), Series-Parallel Resonant Converter (SPRC), and LLC series resonance. Converter (LLC Series Resonant Converter, LLC SRC); the LLCSRC was proposed by CQLee and R. Liu in 1988.

Although a variety of resonant converters are currently available for use with switched power supplies, overall, current switched power supplies still have the following disadvantages:

1. The conventional dual-group output converter load will have an uneven load current, which will cause the output voltage to be adjusted interactively, which cannot meet the specifications.

2. The conventional power supply architecture adopts Hard Switching. Most of the multi-group output voltage regulation strategies use Post Regulator. Although this method can improve the output load regulation rate, its efficiency is improved. Still not enough.

3. The LLC SRC has a higher gain at low frequencies. Compared to the SRC, the LLC SRC has a better regulation effect for applications with a wide range of input voltage variations. However, regardless of LLC SRC or SRC, when the load is light or no load, the output voltage is not properly adjusted due to the resonant inductor and switching frequency within the design range, resulting in a large offset of the output voltage. In the past, when solving light load operation, the method has Burst Mode or Dummy Load, but in the case of dual-group power output, the burst mode cannot be used. When adding a dummy load, Will reduce efficiency.

Therefore, through the above, we can know that the conventional switched power supply and its resonant converter still have many shortcomings and disadvantages. In view of this, the creators of this case tried to study and create a half-bridge dual-output LLC series resonant converter.

The main purpose of this creation is to provide a half-bridge dual-output LLC series resonant converter with an innovative circuit architecture and to solve the load current imbalance and the output voltage cross-regulation that are commonly encountered in conventional two-group output converters. In addition, it can be normally adjusted when the load is light or no load, so there is no possibility that the output voltage has a large offset.

Therefore, in order to achieve the main purpose of this creation, the creator of this case proposed a half-bridge dual-output LLC series resonant converter, which includes: a half bridge rectifier unit, which is composed of a first gold oxide half field effect transistor and a The second gold oxide half field effect transistor is configured to couple an input voltage signal And rectifying the input voltage signal; a first resonant unit is composed of a first resonant inductor and a first resonant capacitor, and coupled to the half bridge rectifying unit to receive the rectified input voltage a first transformer unit coupled to the half bridge rectifier unit, wherein the input voltage signal is transmitted from the primary side coil of the first transformer unit to the secondary side coil of the first transformer unit Converting into a secondary side voltage signal; a first rectifying unit coupled to the first transformer unit to further rectify the secondary side voltage signal; a first output unit having a first load And a resistor coupled to the first rectifying unit; wherein the first resonant inductor, the first resonant capacitor, and the first load resistor form a series resonant circuit, and the series resonant circuit can make the secondary side voltage signal Can be transmitted to the first load resistor without loss, and then output; a second resonant unit is composed of a second resonant inductor and a second resonant capacitor, and Connected to the half-bridge rectifying unit to receive the rectified input voltage signal; a second transformer unit coupled to the half-bridge rectifying unit, wherein the input voltage signal is from the primary side coil of the second transformer unit After being transmitted to the secondary side coil of the first transformer unit, converted into a secondary side voltage signal; a second rectifying unit is coupled to the second transformer unit for further rectifying the secondary side voltage signal; a second output unit having a second load resistor coupled to the second a rectifying unit; wherein the second resonant inductor, the second resonant capacitor and the second load resistor form a series resonant circuit, and the series resonant circuit can enable the secondary side voltage signal to be transmitted to the second without loss a load resistor is further outputted; a voltage dividing unit is coupled to the first output unit and the second output unit for using a first output voltage of the output unit and a second output unit The output voltage is divided; the voltage stability adjusting unit includes at least one operational amplifier coupled to the voltage dividing unit, wherein the voltage stability adjusting unit is configured to stabilize and adjust the first output voltage and the second An output voltage; an optocoupler isolation unit coupled to the voltage stability adjustment unit; and a control unit coupled to the optocoupler isolation unit, wherein the control unit is The first system mosfet transistor and the second mosfet transistor of the switch; and, the opto-isolation means for isolating the system control unit and the first output voltage and second output voltage.

In order to more clearly describe a half-bridge dual-output LLC series resonant converter proposed by the present invention, the following will be described in detail with reference to the drawings. An embodiment of the present creation.

Before describing the half-bridge dual-output LLC series resonant converter of this creation, the half-bridge LLC series resonant converter must be introduced. Please refer to the second figure, which is a circuit diagram of a half bridge LLC series resonant converter. As shown in the second figure, the half bridge LLC series resonant converter is composed of a first transistor Q ₁ and a second transistor Q _{2 .} An input capacitor C _in , a resonant inductor L _r , a resonant capacitor C _r , a transformer T, a first diode D ₁ , a second diode D ₂ , an output capacitor C _O , and a load The resistor R _L is formed, wherein the transformer T has a magnetizing inductance L _m .

Please refer to the third figure for the frequency response diagram of the half-bridge LLC series resonant converter. As shown in the third figure, the first resonant frequency f ₁ and the second resonant frequency f _{2 are} divided into three intervals (special Note that f ₁ and f ₂ are mathematical notation symbols, not component symbols). When the switching frequency f _{s is} greater than the first resonant frequency f ₁ (specially, f _s is a mathematical notation, not a component symbol), the circuit operates at zero. In the voltage switching interval (Region1), the output voltage gain is less than 1; when the switching frequency f _{s is} between the first resonant frequency f ₁ and the second resonant frequency f ₂ , the circuit operates in the zero voltage switching interval (Region 2), and the output voltage The gain is greater than one; when the switching frequency f _{s is} less than the second resonant frequency f ₂ , the circuit operates in a zero current switching interval (Region 3).

In this creation, a half-bridge dual-output LLC series resonant converter was developed based on a half-bridge LLC series resonant converter. Please refer to the fourth and fifth figures, which is a half-bridge dual output LLC of this creation. The architecture diagram of the series resonant converter and its circuit diagram. As shown in the fourth and fifth figures, the half bridge type dual output LLC series resonant converter 1 of the present invention comprises: a half bridge rectifying unit 11, a first resonating unit 12a, a first transformer unit 13a, and a The first rectifying unit 14a, a first output unit 15a, a second resonating unit 12b, a second transformer unit 13b, a second rectifying unit 14b, a second output unit 15b, a voltage dividing unit 16, and a voltage stabilization The adjustment unit 17, an optocoupler isolation unit 18, and a control unit 19.

The half bridge rectifying unit 11 is composed of a first gold oxide half field effect transistor (MOSFET) M ₁ and a second gold oxygen half field effect transistor (MOSFET) M ₂ for coupling an input voltage signal. And the input voltage signal is rectified; and an input capacitor C _in is coupled to the input voltage signal and the half bridge rectifying unit 11 , wherein the input capacitor C _{in is} used for filtering the input voltage signal The noise. As shown in the fifth figure, the first gold-oxide half field effect transistor M ₁ and the second gold-oxide half field effect transistor M ₂ internal system respectively have a first body diode DB ₁ and a second body diode DB body _2; in addition, the first metal-oxide-semiconductor field-effect transistor M ₁ and ₂ the inside of the second metal oxide semiconductor field effect transistor M further has a first parasitic capacitance C _par1 and a second parasitic capacitance C _par2.

The first resonant unit 12a is composed of a first resonant inductor L _r1 and a first resonant capacitor C _r1 , and is coupled to the half bridge rectifying unit 11 to receive the rectified input voltage signal. The first transformer unit 13a is coupled to the half bridge rectifying unit 11, wherein the turns ratio of the primary side coil and the secondary side coil of the first transformer unit 13a is N _P1 : N _S1 (N _P1 , N _{S1 are} not The component symbol is transmitted from the primary side coil of the first transformer unit 13a to the secondary side coil of the first transformer unit 13a, and is converted into a secondary side voltage signal. The first rectifying unit 14a is coupled to the first transformer unit 13a to further rectify the secondary side voltage signal, wherein the first rectifying unit 14a is composed of a first rectifying diode D _R1 And a second rectifying diode D _R2 , and the first rectifying diode D _R1 and the second rectifying diode D _R2 are connected in parallel.

The first output unit 15a is coupled to the first rectifying unit 14a, and is composed of a first load resistor R _L1 and a first output capacitor C _o1 . As shown, the first load resistor R _L1 is Parallel to the first output capacitor C _o1 , and the first output capacitor C _o1 filters the non-DC signal mounted on the secondary side voltage signal. In the present invention, the first resonant inductor L _r1 , the first resonant capacitor C _r1 and the first load resistor R _L1 form a series resonant circuit, and the series resonant circuit can make the secondary side voltage signal have no loss. The ground is transferred to the first load resistor R _L1 and further output.

The second resonant unit 12b is composed of a second resonant inductor L _r2 and a second resonant capacitor C _r2 , and is coupled to the half bridge rectifying unit 11 to receive the rectified input voltage signal. The second transformer unit 13b is coupled to the half bridge rectifying unit 11, wherein the turns ratio of the primary side coil and the secondary side coil of the second transformer unit 13b is N _P2 : N _S2 (N _P2 , N _S2 is not The component symbol is transmitted from the primary side coil of the second transformer unit 13b to the secondary side coil of the second transformer unit 13b, and is converted into a secondary side voltage signal. The second rectifying unit 14b is coupled to the second transformer unit 13b to further rectify the secondary side voltage signal, wherein the second rectifying unit 14b is configured by a third rectifying diode D _R3 And a fourth rectifying diode D _R4 , and the third rectifying diode D _R3 and the fourth rectifying diode D _R4 are connected in parallel.

The second output unit 15b is coupled to the second rectifying unit 14b and is composed of a second load resistor R _L2 and a second output capacitor C _o2 . As shown, the second load resistor R _L2 is Parallel to the second output capacitor C _o2 , and the second output capacitor C _o2 filters the non-DC signal mounted on the secondary side voltage signal. In the present invention, the second resonant inductor L _r2 , the second resonant capacitor C _r2 and the second load resistor R _L2 form a series resonant circuit, and the series resonant circuit can make the secondary side voltage signal have no loss. The ground is transferred to the second load resistor R _L2 and is output.

The voltage dividing unit 16 is coupled to the first output unit 15a and the second output unit 15b for using a first output voltage of the first output unit 15a and a second output unit 15b. The output voltage is divided. As shown in FIG. 5, the voltage dividing unit 16 is composed of a first voltage dividing resistor R _vd1 , a second voltage dividing resistor R _vd2 and a third voltage dividing resistor R _vd3 . The voltage stabilization unit 17 is coupled to the voltage dividing unit 16 and is composed of an operational amplifier TL431, a first resistor R ₁ , a second resistor R ₂ and a first capacitor C ₁ . A resistor R ₁ , a second resistor R ₂ and a first capacitor C ₁ are coupled to the operational amplifier TL431 to provide a low frequency gain, an intermediate frequency gain and a high frequency gain of the operational amplifier TL431 , so that the voltage is stable. The adjusting unit 17 can stabilize and adjust the first output voltage and the second output voltage; and the second resistor R ₂ is in series with the first capacitor C ₁ , and the second resistor R ₂ and the first resistor R ₁ is parallel.

Also, the opto-isolation unit 18 coupled to the line voltage stabilization adjusting unit 17, and the opto-isolated from the system unit 18 a photocoupler PC817, a third resistor R ₃ and a fourth resistor which R ₄ is composed. The control unit 19 is a high pressure the L6599 resonant controller, which is coupled to the opto-based isolation unit 18, wherein the system control unit 19 for controlling the first metal-oxide-semiconductor field-effect transistor M ₁ and the second metal The switch of the oxygen half field effect transistor M ₂ ; and the optocoupler isolation unit 18 is used to isolate the control unit 19 from the first output voltage and the second output voltage.

Thus, the above-mentioned system has completely and clearly explained the architectural diagram and circuit diagram of the half-bridge dual-output LLC series resonant converter of the present invention; then, the following will demonstrate the half-bridge type of the creation by the presentation of experimental data. The feasibility and efficiency of a dual output LLC series resonant converter. Please refer to the following table (1) and Table (2) for the data sheets used in the experiment:

Please refer to the sixth figure, which is a waveform diagram of the half-bridge rectifying unit and the resonant tank element measured by the input voltage of 380V. (A) of the sixth figure shows the output voltage/current of 12V/2A and 5V/0.3A. Output voltage / current, Figure 6 (b) shows 12V / 2A output voltage / current and 5V / 15A The output voltage/current, Figure 6 (c) shows the output voltage/current of 12V/35A and the output voltage/current of 5V/0.3A, and the graph (d) of the sixth figure shows the output voltage of 12V/35A. / Current and 5V / 15A output voltage / current.

Continuing, please refer to the seventh diagram, which is a waveform diagram of the half-bridge rectifying unit and the resonant tank element measured at an input voltage of 390 V, wherein (a) of the seventh figure shows the output voltage/current of 12 V/0.3 A and 5V/0.3A output voltage/current, Figure 7 (b) shows the output voltage/current of 12V/2A and the output voltage/current of 5V/15A. Figure 7 (c) shows 12V/35A Output voltage/current and output voltage/current of 5V/0.3A, and (d) of the seventh figure shows the output voltage/current of 12V/35A and the output voltage/current of 5V/15A.

Finally, please refer to the eighth figure, which is a waveform diagram of the half-bridge rectifying unit and the resonant tank element measured at an input voltage of 400V. (A) of the eighth figure shows the output voltage/current of 12V/0.3A and 5V. /0.3A output voltage / current, Figure 8 (b) shows 12V / 2A output voltage / current and 5V / 15A output voltage / current, Figure 8 (c) shows 12V / 35A output Voltage/current and 5V/0.3A output voltage/current, and Figure 8(d) shows 12V/35A output voltage/current and 5V/15A output voltage/current.

Thus, the above description has completely and clearly disclosed all embodiments of the half bridged dual output LLC series resonant converter of the present invention, via As mentioned, the author has the following advantages:

1. The innovative circuit architecture of the half-bridge dual-output LLC series resonant converter of the present invention can solve the phenomenon that the load current unevenness and the output voltage are alternately adjusted in the conventional two-group output converter.

2. The half-bridge dual-output LLC series resonant converter of the present invention can be normally adjusted when the load is light or no load, so that there is no large offset of the output voltage.

The detailed description of the present invention is intended to be limited to the specific scope of the present invention, and is not intended to limit the scope of the present invention. Changes should be included in the scope of the patent in this case.

1'‧‧‧Switching LED Driver Circuit

11'‧‧‧Rectifier unit

12’‧‧‧Power Factor Correction Unit

13’‧‧‧DC/DC conversion unit

14’‧‧‧Output unit

15’‧‧‧PFC Control Unit

16’‧‧‧Converter Control Unit

Q ₁ ‧‧‧First transistor

Q ₂ ‧‧‧Second transistor

C _in ‧‧‧Input capacitance

L _r ‧‧‧Resonant inductance

C _r ‧‧‧Resonance capacitor

T‧‧‧Transformer

D ₁ ‧‧‧First Diode

D ₂ ‧‧‧Secondary

C _O ‧‧‧ output capacitor

R _L ‧‧‧Load resistor

L _m ‧‧‧Magnetic inductance

11‧‧‧Half-bridge rectifier unit

12a‧‧‧First Resonance Unit

13a‧‧‧First transformer unit

14a‧‧‧First rectification unit

15a‧‧‧First output unit

12b‧‧‧second resonance unit

13b‧‧‧Second transformer unit

14b‧‧‧Secondary rectifier unit

15b‧‧‧second output unit

1‧‧‧Half-bridge dual output LLC series resonant converter

16‧‧‧Voltage unit

17‧‧‧Voltage stability adjustment unit

18‧‧‧optical coupling isolation unit

19‧‧‧Control unit

M ₁ ‧‧‧First Golden Oxygen Half Field Effect Crystal

M ₂ ‧‧‧second gold oxygen half field effect transistor

DB ₁ ‧‧‧ first body diode

DB ₂ ‧‧‧Second body diode

C _in ‧‧‧Input capacitance

C _par1 ‧‧‧first parasitic capacitance

C _par2 ‧‧‧Second parasitic capacitance

L _r1 ‧‧‧First resonant inductor

C _r1 ‧‧‧First Resonant Capacitor

D _R1 ‧‧‧First Rectifier Diode

D _R2 ‧‧‧Second rectifying diode

R _L1 ‧‧‧First load resistor

C _o1 ‧‧‧first output capacitor

L _r2 ‧‧‧Second resonant inductor

C _r2 ‧‧‧second resonant capacitor

D _R3 ‧‧‧third rectifier diode

D _R4 ‧‧‧fourth rectifier diode

R _L2 ‧‧‧second load resistor

C _o2 ‧‧‧second output capacitor

R _vd1 ‧‧‧First voltage divider resistor

R _{vd2 ‧‧‧Second} voltage divider resistor

R _vd3 ‧‧‧ third voltage divider resistor

TL431‧‧‧Operational Amplifier

R ₁ ‧‧‧first resistance

R ₂ ‧‧‧second resistance

C ₁ ‧‧‧first capacitor

PC817‧‧‧Optocoupler

R ₃ ‧‧‧third resistor

R ₄ ‧‧‧fourth resistor

L6599‧‧‧High Voltage Resonant Controller

The first figure is a schematic diagram of a switched power supply that is conventional; the second picture is a circuit diagram of a half bridge LLC series resonant converter; the third picture is a frequency response diagram of a half bridge LLC series resonant converter; The figure is a half-bridge dual-output LLC series resonant converter architecture diagram; the fifth diagram is a half-bridge dual-output LLC series resonant converter circuit diagram; the sixth figure is measured by the input voltage 380V Waveform diagram of the half bridge rectifier unit and the resonant tank component; the seventh diagram is a waveform diagram of the half bridge rectifier unit and the resonant tank component measured by the input voltage 390V; The eighth figure is a waveform diagram of the half-bridge rectifying unit and the resonant tank element measured at an input voltage of 400V.

1‧‧‧Half-bridge dual output LLC series resonant converter

M ₁ ‧‧‧First Golden Oxygen Half Field Effect Crystal

M ₂ ‧‧‧second gold oxygen half field effect transistor

DB ₁ ‧‧‧ first body diode

DB ₂ ‧‧‧Second body diode

C _in ‧‧‧Input capacitance

C _par1 ‧‧‧first parasitic capacitance

C _par2 ‧‧‧Second parasitic capacitance

L _r1 ‧‧‧First resonant inductor

C _r1 ‧‧‧First Resonant Capacitor

D _R1 ‧‧‧First Rectifier Diode

D _R2 ‧‧‧Second rectifying diode

R _L1 ‧‧‧First load resistor

C _o1 ‧‧‧first output capacitor

L _r2 ‧‧‧Second resonant inductor

C _r2 ‧‧‧second resonant capacitor

D _R3 ‧‧‧third rectifier diode

D _R4 ‧‧‧fourth rectifier diode

R _L2 ‧‧‧second load resistor

C _o2 ‧‧‧second output capacitor

R _vd1 ‧‧‧First voltage divider resistor

R _{vd2 ‧‧‧Second} voltage divider resistor

R _vd3 ‧‧‧ third voltage divider resistor

TL431‧‧‧Operational Amplifier

R ₁ ‧‧‧first resistance

R ₂ ‧‧‧second resistance

C ₁ ‧‧‧first capacitor

PC817‧‧‧Optocoupler

R ₃ ‧‧‧third resistor

R ₄ ‧‧‧fourth resistor

L6599‧‧‧High Voltage Resonant Controller

Claims (13)

A half-bridge dual output LLC series resonant converter includes a half bridge rectifier unit, which is composed of a first gold oxide half field effect transistor (MOSFET) and a second gold oxide half field effect transistor (MOSFET). The first resonant unit is composed of a first resonant inductor and a first resonant capacitor, and is coupled to the half-bridge rectifier unit. The first resonant unit is coupled to the first resonant capacitor and coupled to the half-bridge rectifier unit. Receiving the rectified input voltage signal; a first transformer unit coupled to the half bridge rectifying unit, wherein the input voltage signal is transmitted from the primary side coil of the first transformer unit to the first transformer unit After the secondary side coil is converted into a secondary side voltage signal; a first rectifying unit is coupled to the first transformer unit to further rectify the secondary side voltage signal; a first output The unit has a first load resistance coupled to the first rectifying unit; wherein the first resonant inductor, the first resonant capacitor, and the first load resistor form a series resonance a circuit, the series resonant circuit can enable the secondary side voltage signal to be transmitted to the first load resistor without loss, and then output; a second resonant unit is composed of a second resonant inductor and a second resonant capacitor, and is coupled to the half bridge rectifier unit to receive the rectified input voltage signal; a second transformer unit is coupled In the half bridge rectifier unit, the input voltage signal is transmitted from the primary side coil of the second transformer unit to the secondary side coil of the first transformer unit, and is converted into a secondary side voltage signal; The second rectifying unit is coupled to the second transformer unit for further rectifying the secondary side voltage signal; a second output unit having a second load resistor coupled to the second rectifying unit The second resonant inductor, the second resonant capacitor and the second load resistor form a series resonant circuit, and the series resonant circuit can enable the secondary side voltage signal to be transmitted to the second load resistor without loss. And being outputted; a voltage dividing unit is coupled to the first output unit and the second output unit for using a first output voltage and a second of the first output unit a second output voltage of the output unit is divided; a voltage stability adjusting unit includes at least one operational amplifier coupled to the voltage dividing unit, wherein the voltage stability adjusting unit is configured to stabilize and adjust the first An output voltage and the second output voltage; an optocoupler isolation unit coupled to the voltage stability adjustment unit; a control unit is coupled to the optocoupler isolation unit, wherein the control unit is configured to control a switch of the first metal oxide half field effect transistor and the second gold oxygen half field effect transistor; and the optocoupler The isolation unit is configured to isolate the control unit from the first output voltage and the second output voltage. The half bridge type dual output LLC series resonant converter according to claim 1, wherein the first gold oxide half field effect transistor and the second gold oxygen half field effect transistor internal system respectively have a first The body diode and a second body diode. The half bridge type dual output LLC series resonant converter according to claim 2, wherein the first gold oxide half field effect transistor and the second gold oxide half field effect transistor respectively have a first Parasitic capacitance and a second parasitic capacitance. The half-bridge dual-output LLC series resonant converter according to the first aspect of the invention, wherein the first rectifying unit is composed of a first rectifying diode and a second rectifying diode, and The first rectifying diode and the second rectifying diode are connected in parallel. The half bridge type dual output LLC series resonant converter according to claim 1, wherein the second rectifying unit is composed of a third rectifying diode and a fourth rectifying diode, and The third rectifying diode is connected in parallel with the fourth rectifying diode. The half-bridge dual-output LLC series resonant converter according to claim 1, wherein the first output unit further includes a first output capacitor connected in parallel with the first load resistor for filtering A non-direct current signal above the secondary side voltage signal. The half-bridge dual-output LLC series resonant converter according to claim 1, wherein the second output unit further includes a second output capacitor connected in parallel with the second load resistor for filtering A non-direct current signal above the secondary side voltage signal. The half bridge type dual output LLC series resonant converter according to claim 1, wherein the voltage dividing unit is composed of a first voltage dividing resistor, a second voltage dividing resistor and a third voltage dividing resistor. Composed of. The half-bridge dual-output LLC series resonant converter according to the first aspect of the invention, wherein the voltage stability adjusting unit further comprises a first resistor, a second resistor and a first capacitor, which are coupled to The operational amplifier provides a low frequency gain, an intermediate frequency gain and a high frequency gain of the operational amplifier. The two-bridge dual output LLC series resonant converter of claim 9, wherein the second resistor is in series with the first capacitor, and the second resistor is connected in parallel with the first resistor. The half-bridge dual-output LLC series resonant converter according to claim 9, wherein the optocoupler isolation unit is composed of an optical coupler, a third resistor and a fourth resistor. The half bridge type dual output LLC series resonant converter according to claim 1, wherein the control unit is a high voltage resonant controller. The half-bridge dual-output LLC series resonant converter according to the first aspect of the invention, further comprising an input capacitor coupled to the input voltage signal and the half-bridge rectifying unit.