CN204465373U - Synchronous rectifier control circuit - Google Patents
Synchronous rectifier control circuit Download PDFInfo
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- CN204465373U CN204465373U CN201520125665.5U CN201520125665U CN204465373U CN 204465373 U CN204465373 U CN 204465373U CN 201520125665 U CN201520125665 U CN 201520125665U CN 204465373 U CN204465373 U CN 204465373U
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Abstract
A kind of synchronous rectifier control circuit, for controlling the power switch in the synchronous rectifier of power supply changeover device.Synchronous rectifier control circuit comprises signal processing unit and driver element, and signal processing unit is electrically connected on transformer secondary output winding, and driver element is electrically connected on power switch and signal processing unit.The output current of signal processing unit sensing secondary winding, and determine that power switch operates in the quantity of following state.When output current is less than the first predetermined value, a power switch in each switch module operates in following state; When output current is greater than the second predetermined value, all power switchs all operate in following state; When output current is between the first predetermined value and the second predetermined value, signal processing unit increases along with output current and increases the quantity operating in the power switch of following state.
Description
Technical field
The utility model relates to a kind of ON-OFF control circuit, particularly a kind of synchronous rectifier control circuit of circuit of synchronous rectification.
Background technology
Tradition uses the rectifier system of diode or Schottky diode because forward conducting voltage is large, and overall losses becomes the dominant loss of power supply changeover device.Mos field effect transistor has that conducting resistance is low, switching time is short, input impedance is high, become the rectifier cell of the power supply changeover device first-selection of low-voltage and high-current, according to the Volume control of mos field effect transistor, thus the technology of synchronous rectification (Synchronous Rectification, SR) is had.
Coordinating and consult Fig. 1, is the circuit diagram of the synchronous rectifier control circuit of prior art.Synchronous rectifier control circuit 4 is electrically connected on the secondary winding of transformer, in order to the mode of operation of the power switch of control synchronization rectifier.Synchronous rectifier is electrically connected on the transformer T secondary winding of power supply changeover device (being such as DC-DC power converter), synchronous rectifier comprises the first switch module SR1 and second switch module SR2, first switch module SR1 and second switch module SR2 comprises four power switchs respectively, wherein the first switch module SR1 comprises power switch MOS11-MOS14, and second switch group SR2 comprises power switch MOS21-MOS24.Power switch MOS11-MOS14 in first switch module SR1 is in being connected in parallel, and the power switch MOS21-MOS24 in second switch module SR2 is also in being connected in parallel.More specifically, in the first switch module SR1 and second switch module SR2, the grid of power switch MOS11-MOS24 is all electrically connected on synchronous rectifier control circuit 4, and drain electrode is all electrically connected on the secondary winding of transformation T, and source electrode is all electrically connected earth terminal.
By this, synchronous rectifier control circuit 4 can control the mode of operation of all power switchs in the first switch module SR1 and second switch module SR2 simultaneously; Such as make all power switch MOS11-MOS24 all operationss in the first switch module SR1 and second switch module SR2 in cut-off state, or all power switch MOS11-MOS24 in the first switch module SR1 and second switch module SR2 are followed, and drive singal that synchronous rectifier control circuit 4 exports carry out switching action.
The power switch MOS11-MOS24 of aforesaid synchronous rectifier possesses the simple and easy and simple feature of circuit of control mode.But, after power supply changeover device starts, no matter power supply changeover device operates in heavy duty or underloading, the drive singal that all power switch MOS11-MOS24 all can export according to synchronous rectifier control circuit 4 carries out switching action, and this makes the switch cost of power supply changeover device when underloading effectively to reduce.
Utility model content
Technical problem to be solved in the utility model is in providing a kind of synchronous rectifier control circuit, be applied to the synchronous rectifier in control one power supply changeover device, according to the output current of power supply changeover device secondary winding, synchronous rectifier control circuit determines that the power switch in synchronous rectifier operates in the quantity of following state, and when the output current increases, increase and operate in the quantity of the power switch of following state, to reduce the switch cost of power supply changeover device when underloading.
To achieve these goals, the utility model provides a kind of synchronous rectifier control circuit, be applicable to a synchronous rectifier of control one power supply changeover device, this synchronous rectifier is electrically connected on the secondary winding of a transformer of this power supply changeover device and comprises multiple switch module, respectively this switch module comprises multiple power switch, and this synchronous rectifier control circuit comprises:
One output current of the secondary winding of one this transformer of sensing, and the signal processing unit operating in the quantity of following state of the plurality of power switch is determined in this output current, be electrically connected on the secondary winding of this transformer; And
Multiple driver element, is electrically connected on the plurality of switch module and this signal processing unit respectively,
Wherein, when this output current is less than first predetermined value, one of them power switch in the plurality of switch module operates in following state, when this output current is greater than second predetermined value, the plurality of power switch all operates in following state, this output current is when this first predetermined value and this second predetermined value, and this signal processing unit increases along with this output current and increases the quantity operating in the power switch of following state.
Above-mentioned synchronous rectifier control circuit, wherein, this signal processing unit comprises a current sense end, multiple drive singal output and multiple control signal output, this current sense end is electrically connected on the secondary winding of this transformer, respectively this driver element comprises a driving signal input, multiple control signal input and multiple output, the plurality of drive singal output of this signal processing unit is electrically connected on the plurality of driving signal input of the plurality of driver element, the plurality of control signal output of this signal processing unit is electrically connected on this control signal input of the plurality of driver element, respectively the plurality of output of this driver element is electrically connected on one of them power switch respectively.
Above-mentioned synchronous rectifier control circuit, wherein, respectively the quantity of the plurality of control signal input of this driver element is P, and respectively the quantity of the plurality of output of this driver element is Q, and it meets following condition:
P＝Q-1。
Above-mentioned synchronous rectifier control circuit, wherein, this signal processing unit comprises a signal processor and a pulse width modulation controller, this signal processor comprises this current sense end and the plurality of control signal output, and this pulse width modulation controller comprises the plurality of drive singal output.
Above-mentioned synchronous rectifier control circuit, wherein, this signal processing unit comprises a signal processor and a switching device, this signal processor comprises this current sense end, the plurality of control signal output, one activation end, one switches control end and multiple operation mode signals output, this switch unit comprises the plurality of drive singal output, one activation end, one switches control end and multiple driving selecting side, this activation end of this signal processor and this switching controls end are electrically connected on this activation end and the switching controls end of this switching device respectively, the plurality of operation mode signals output of this signal processor is electrically connected on the plurality of driving selecting side of this switch unit respectively.
Above-mentioned synchronous rectifier control circuit, wherein, this driver element comprises a master driver and secondary driver, this master driver and this driver comprise one first respectively and drive input, one second drives input, one first control end, one second control end, one first drive output and one second drive output, this of this master driver and this driver first drives input and second to drive input to be connected and is this driving signal input of this driver element, this second control end of this master driver is the first control signal input of this driver element, this first control end of this driver is this second control signal input of this driver element, this second control end of this driver is the 3rd control signal input of this driver element.
Above-mentioned synchronous rectifier control circuit, wherein, this driver element comprises a master driver and secondary driver, and this master driver comprises one first and drives input and one first drive output, and this driver comprises one first and drive input, second drives input, one the 3rd drives input, one four-wheel drive input, one first control end, one second control end, one the 3rd control end, one the 4th control end, one first drive output, one second drive output, one the 3rd drive output and a four-wheel drive output, this first driving input of this master driver, this the first driving input of this driver, this second drives input and the 3rd to drive input to be connected and is this driving signal input of this driver element, this first control end of this driver, this second control end and the 3rd control end are respectively this first control signal input of this driver element, this the second control signal input and the 3rd control signal input.
Above-mentioned synchronous rectifier control circuit, wherein, this driver element comprises a master driver and a switching circuit, and this master driver comprises one first and drives input, one second drives input, one the 3rd drives input, one four-wheel drive input, one first drive output, one second drive output, one the 3rd drive output and one the 4th four-wheel drive output, this first driving input, this the second driving input, 3rd drives input and this four-wheel drive input to be connected and is this driving signal input of this driver element, and this switching circuit comprises one first switch input terminal, one second switch input, one the 3rd switch input terminal, one the 4th switch input terminal, one first switch activation end, one second switch activation end, one the 3rd switch activation end, one the 4th switch activation end, one first output switching terminal, one second switch output, one the 3rd output switching terminal and one the 4th output switching terminal, this first to fourth switch input terminal of this switching circuit is electrically connected on this first to fourth drive output of this master driver respectively, this second to the 4th switch activation end of this switching circuit is respectively this second to the 4th control signal input of this driver element, and this first to fourth output switching terminal of this switching circuit is this first to fourth output of this driver element.
Above-mentioned synchronous rectifier control circuit, wherein, the plurality of quantity of the plurality of power switch operating in following state is directly proportional to the size of this output current.
Beneficial functional of the present utility model is:
According to the output current of power supply changeover device secondary winding, the utility model determines that the power switch in synchronous rectifier operates in the quantity of following state, and when the output current increases, increase and operate in the quantity of the power switch of following state, to reduce the switch cost of power supply changeover device when underloading.
Below in conjunction with the drawings and specific embodiments, the utility model is described in detail, but not as to restriction of the present utility model.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of the synchronous rectifier control circuit of prior art;
Fig. 2 is the circuit diagram of the utility model embodiment synchronous rectifier control circuit;
Fig. 3 is the sequential chart of corresponding output current of the present utility model and on off state;
Fig. 4 a is the circuit block diagram of the signal processing unit of the utility model first embodiment;
Fig. 4 b is the circuit block diagram of the signal processing unit of the utility model second embodiment;
Fig. 4 c is the circuit block diagram of the signal processing unit of the utility model the 3rd embodiment;
Fig. 5 a is the circuit block diagram of the driver element of the utility model first embodiment;
Fig. 5 b is the circuit block diagram of the driver element of the utility model second embodiment;
Fig. 5 c is the circuit block diagram of the driver element of the utility model the 3rd embodiment.
Wherein, Reference numeral
1 signal processing unit
10 signal processors
11 switching devices
12 pulse width modulation controllers
20 driver elements
30 master drivers
32 drivers
40 switching circuits
4 synchronous rectifier control circuits
Cntl2 first control signal input
Cntl3 second control signal input
Cntl4 the 3rd control signal input
Cntl_1 first control end
Cntl_2 second control end
Cntl_3 the 3rd control end
Cntl_4 the 4th control end
Drv_In_1 first drives input
Drv_In_2 second drives input
Drv_In_3 the 3rd drives input
Drv_In_4 four-wheel drive input
Drv_Out_1 first drive output
Drv_Out_2 second drive output
Drv_Out_3 the 3rd drive output
Drv_Out_4 four-wheel drive output
Drv1 first drive singal output
Drv2 second drive singal output
DrvI driving signal input
Drv1_Select_1-Drv2_Select_2 drives selecting side
Enable activation end
I1 first set point
I2 second set point
I_SENSE current sense end
MOS11-MOS24 power switch
MOS2_EN first control signal output
MOS3_EN second control signal output
MOS4_EN the 3rd control signal output
Out1 first output
Out2 second output
Out3 the 3rd output
Out4 the 4th output
SR1, SR2 switch module
SR1_MODE1-SR2_MODE2 operates mode signals output
SW switching controls end
Sw_1_En first switch activation end
Sw_2_En second switch activation end
Sw_3_En the 3rd switch activation end
Sw_4_En the 4th switch activation end
Sw_In_1 first switch input terminal
Sw_In_2 second switch input
Sw_In_3 the 3rd switch input terminal
Sw_In_4 the 4th switch input terminal
Sw_Out_1 first output switching terminal
Sw_Out_2 second switch output
Sw_Out_3 the 3rd output switching terminal
Sw_Out_4 the 4th output switching terminal
T transformer
Embodiment
Below in conjunction with accompanying drawing, structural principle of the present invention and operation principle are described in detail:
Coordinating and consult Fig. 2, is the circuit diagram of the synchronous rectifier control circuit of the utility model embodiment.Circuit of synchronous rectification is applicable to a synchronous rectifier of control one power supply changeover device, synchronous rectifier is electrically connected on the transformer T secondary winding of power supply changeover device, and comprise multiple switch module SR1-SR2, each switch module SR1, SR2 comprise multiple power switch MOS11-MOS24, power switch can such as mos field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET).What illustrate is, the circuit of synchronous rectification of each embodiment of the present utility model be all respectively control two switch modules four power switchs as illustrative example, so when reality is implemented, the quantity of switch module and power switch can adjust according to actual requirement.The drain electrode of power switch MOS11-MOS24 is electrically connected on the secondary winding of transformer T respectively, and source electrode then connects earth terminal.
Synchronous rectifier control circuit comprises a signal processing unit 1 and multiple driver element 20.Signal processing unit 1 is electrically connected on the secondary winding of transformer T, in order to sense the output current of secondary winding; Wherein, signal processing unit 1 through the output current of current transformer (current transformer) inductive secondary winding in a non contact fashion, or can obtain the output current of secondary winding with the way of contact through current-sense resistor (shunt resistor).Signal processing unit 1 comprises a current sense end I_SENSE, multiple drive output and multiple control signal output.In the utility model, signal processing unit 1 comprises two drive output and three control output ends, and is respectively the first drive singal output Drv1, the second drive singal output Drv2, the first control signal output MOS2_EN, the second control signal output MOS3_EN and the 3rd control signal output MOS4_EN.
Driver element 20 comprises a driving signal input DrvI, multiple control signal input and multiple output, and when the quantity of control signal input is P, when the quantity of output is Q, meets following condition: P=Q-1.In utility model, driver element 20 comprises three control signal inputs, and is respectively the first control signal input Cntl2, the second control signal input Cntl3 and the 3rd control signal input Cntl4.Driver element 20 also comprises four outputs, and is respectively the first output Out1, the second output Out2, the 3rd output Out3 and the 4th output Out4.
First drive singal output Drv1 of signal processing unit 1 is electrically connected on the driving signal input DrvI of a driver element 20 wherein, and the second drive singal output Drv2 is electrically connected on the driving signal input DrvI of another driver element 20.First control signal output MOS2_EN of signal processing unit 1 is electrically connected on the first control signal input Cntl2 of driver element 20, second control signal output MOS3_EN is electrically connected on the second control signal input Cntl3 of driver element 20, and the 3rd control signal output MOS4_EN is electrically connected on the 3rd control signal input Cntl4 of driver element 20.
First output Out1, the second output Out2 of the driver element 20 above being positioned at as shown in Figure 2, the 3rd output Out3 and the 4th output Out4 are electrically connected on the grid of power switch MOS11-MOS14 respectively, and the first output Out1, the second output Out2 of the driver element 20 below being positioned at, the 3rd output Out3 and the 4th output Out4 are electrically connected on the grid of power switch MOS21-MOS24 respectively.
The current sense end I_SENSE of signal processing unit 1 is electrically connected on the secondary winding of transformer T, and senses the output current of secondary winding.Signal processing unit 1 operates in the quantity of the power switch MOS11-MOS24 of cut-off state with decision according to sensed output current, and send corresponding the first control signal input Cntl2, the second control signal input Cntl3 that control signal to driver element 20 and the 3rd control signal input Cntl4, to control the mode of operation of power switch MOS11-MOS24 by the first control signal output MOS2_EN, the second control signal output MOS3_EN and the 3rd control signal output MOS4_EN.
The mode of operation of power switch MOS11-MOS24 comprises cut-off state and following state, in cut-off state, the grid of power switch MOS11-MOS24 receives pick-off signal (in this case continuously low level signal) when inputting, not conducting between the source electrode of power switch MOS11-MOS24 and drain electrode is cut-off state; At following state, power switch MOS11-MOS24 follows the drive singal that driver element 20 sends and carries out switching action; Wherein, drive singal is made up of staggered low level signal and high levle signal.
When the output current of transformer T secondary winding is less than the first set point I1 (as shown in Figure 3), synchronous rectifier control circuit makes one of them power switch in switch module SR1, SR2, such as operate in following state for power switch MOS11 and MOS21, other power switch MOS12, MOS13, MOS14, MOS22, MOS23 and MOS24 then operate in cut-off state; In other words, only power switch MOS11 and MOS21 not operation in cut-off state.
When the output current of transformer T secondary winding is greater than the second set point I2 (as shown in Figure 3), synchronous rectifier control circuit makes all power switch MOS11-MOS24 all operate in following state, and the drive singal that power switch MOS11-MOS24 all follows driver element 20 output carries out switching action; In other words, all power switch MOS11-MOS24 all not operation in cut-off state.Wherein, the second set point I2 can be such as current value when power supply changeover device works in semi-load), and the second set point I2 is greater than the first set point I1.
When the output current of transformer T secondary winding is between the first set point I 1 and the second set point I2, and when being increased to the second set point I2 gradually by the first set point I1, synchronous rectifier control circuit makes the quantity of the power switch MOS11-MOS24 operating in following state increase gradually.In brief, when the output current of transformer T secondary winding is little, operate in the quantity few (quantity also namely operating in the power switch MOS11-MOS24 of cut-off state is many) of the power switch MOS11-MOS24 of following state; When the output current of secondary winding is large, operate in the quantity many (quantity also namely operating in the power switch MOS11-MOS24 of cut-off state is few) of the power switch MOS11-MOS24 of following state; And preferably, the quantity of power switch MOS11-MOS24 operating in following state is directly proportional to the numerical value of output current.By this, the switch cost of power switch when power supply changeover device operates in underloading can effectively be reduced.
Lower list is below coordinated to be described once the mode of operation of synchronous rectifier control circuit of the present utility model.
Table one is the detailed operating data of the synchronous rectifier control circuit of Fig. 2, and wherein L table exports low level signal, and H table exports high levle signal; " cut-off " represents that power switch MOS11-MOS24 operates in cut-off state, i.e. not conducting between power switch MOS11-MOS24 source electrode and drain electrode; " follow " and represent that power switch MOS11-MOS24 operates in following state, the drive singal that first or second drive singal output Drvl, Drv2 that namely power switch MOS11-MOS24 follows signal processing unit 1 exports carries out switching action.
In brief, the control method of synchronous rectifier of the present invention is an output current of the secondary winding first sensing transformer T, and when output current is greater than the first set point and is less than the second set point, according to the mode of operation of the power switch MOS11-MOS24 in output current control switch module SR1, SR2, and when output current increases gradually, the power switch MOS11-MOS24 increased in switch module SR1, SR2 operates in the quantity of following state.
Coordinating and consult Fig. 4 a, is the block diagram of the signal processing unit of the utility model first embodiment.Signal processing unit 1 comprises signal processor 10, signal processor 10 comprises current sense end I_SENSE, the first to the 3rd control signal output MOS2_EN-MOS4_EN, the first drive singal output Drv1 and the second drive singal output Drv2, and respectively in order to as the current sense end I_SENSE of signal processing unit 1, the first to the 3rd control signal output MOS2_EN-MOS4_EN, the first drive singal output Drv1 and the second drive singal output Drv2.
Coordinating and consult Fig. 4 b, is the block diagram of the signal processing unit of the utility model second embodiment.Signal processing unit 1 comprises signal processor 10 and a pulse width modulation controller 12; Signal processor 10 comprises current sense end I_SENSE and first to the 3rd control signal output MOS2_EN-MOS4_EN, and respectively in order to the current sense end I_SENSE and first as signal processing unit 1 to the 3rd control signal output MOS2_EN-MOS4_EN.
Pulse width modulation controller 12 comprises the first drive singal output Drv1 and the second drive singal output Drv2, and in order to as the first drive singal output Drv1 of signal processing unit 1 and the second drive singal output Drv2.
Coordinating and consult Fig. 4 c, is the block diagram of the signal processing unit of the utility model the 3rd embodiment.Signal processing unit 1 comprises signal processor 10 and switching device 11; Signal processor 10 comprises a current sense end I_SENSE, the first to the 3rd control signal output MOS2_EN-MOS4_EN, an activation end Enable, switch control end SW and multiple operation mode signals output SR1_MODE1-SR2_MODE2, current sense end I_SENSE and first to the 3rd control signal output MOS2_EN-MOS4_EN in order to the current sense end I_SENSE and first as signal processing unit 1 to the 3rd control signal output MOS2_EN-MOS4_EN.
Switching device 11 comprises one first drive singal output Drv1, one second drive singal output Drv2, an activation end Enable, switches control end SW and multiple driving selecting side Drv1_Select_1-Drv2_Select_2, the first drive singal output Drv1 and one second drive singal output Drv2 in order to as the first drive singal output Drv1 of signal processing unit 1 and one second drive singal output Drv2.
The activation end Enable of signal processor 10 and switching controls end SW is electrically connected on activation end Enable and the switching controls end SW of switching device 11 respectively, in order to control the operating state of switching device 11.The operation mode signals output SR1_MODE1-SR2_MODE2 of signal processor 10 is electrically connected on the driving selecting side Drv1_Select_1-Drv2_Select_2 of switching device 11 respectively, and switching device 11 is according to operating the signal of mode signals output SR1_MODE1-SR2_MODE2 output to determine the mode of operation of power switch MOS11-MOS24.
The mode of operation below coordinating lower list two just to include the synchronous rectifier control circuit of the signal processing unit of the 3rd embodiment is described.
Table two is for having the detailed operating data of the synchronous rectifier control circuit of the signal processing unit shown in Fig. 4 c, and wherein X shows arbitrary signal output, and L table exports low level signal, and H table exports high levle signal; " cut-off " represents that power switch MOS11-MOS24 operates in cut-off state, i.e. not conducting between power switch MOS11-MOS24 source electrode and drain electrode; " follow " and represent that power switch MOS11-MOS24 operates in following state, the drive singal that the first or second drive output Drvl, Drv2 that namely power switch MOS11-MOS24 follows signal processing unit 1 export switches.
Coordinating and consult Fig. 5 a, is the circuit block diagram of the driver element of the utility model first embodiment.Driver element 20 can be made up of master driver 30 and secondary driver 32, and master driver 30 and secondary driver 32 comprise the first driving input Drv_In_1, second respectively and drive input Drv_In_2, the first control end Cntl_1, the second control end Cntl_2, the first drive output Drv_Out_1 and the second drive output Drv_Out_2.
First of master driver 30 drives input Drv_In_1, second to drive input Drv_In_2, and first of secondary driver 32 drives input Drv_In_1, second to drive input Drv_In_2 to be connected and in order to the driving signal input DrvI as driver element 20.
Second control end Cntl_2 of master driver 30 is in order to the 21 control signal input Cntl2 as driver element 20, first control end Cntl_1 of secondary driver 32 is in order to the second control signal input Cntl3 as driver element 20, second control end Cntl_2 of secondary driver 32 is in order to the 3rd control signal input Cntl4 as driver element 20, first control end Cntl_1 of master driver 30 is electrically connected on an enable signal, and remains on the state be enabled at any time.
First drive output Drv_Out_1 of master driver 30 and the second drive output Drv_Out_2 respectively in order to as the first output Out1 of driver element 20 and the second output Out2, the first drive output Drv_Out_1 of secondary driver 32 and the second drive output Drv_Out_2 respectively in order to as the 3rd output Out3 of driver element 20 and the 4th output Out4.
Coordinating and consult Fig. 5 b, is the circuit block diagram of the driver element of the utility model second embodiment.Driver element 20 can be made up of master driver 30 and secondary driver 32; Master driver 30 and secondary driver 32 comprise the first driving input Drv_In_1 and the first drive output Drv_Out_1 respectively.
Secondary driver 32 also comprises the second driving input Drv_In_2, the 3rd and drives input Drv_In_3, four-wheel drive input Drv_In_4, the first control end Cntl_1, the second control end Cntl_2, the 3rd control end Cntl_3, the 4th control end Cntl_4, the second drive output Drv_Out_2, the 3rd drive output Drv_Out_3 and four-wheel drive output Drv_Out_4.
First of master driver 30 drives input Drv_In_1, and first of secondary driver 32 drives input Drv_In_1, second to drive input Drv_In_2, the 3rd to drive input Drv_In_3 to be connected and in order to the driving input Drv1 as driver element 20.
First control end Cntl_1, the second control end Cntl_2 of secondary driver 32 and the 3rd control end Cntl_3 are respectively in order to as the first control signal input Cntl2, the second control signal input Cntl3 of driver element 20 and the 3rd control signal input Cntl4.
First drive output Drv_Out_1 of master driver 30 is in order to the first output Out1 as driver element 20, and the first drive output Drv_Out_1, the second drive output Drv_Out_2 of secondary driver 32 and the 3rd drive output Drv_Out_3 are respectively in order to as the second output Out2, the 3rd output Out3 of driver element 20 and the 4th output Out4.
Coordinating and consult Fig. 5 c, is the circuit block diagram of the driver element of the utility model the 3rd embodiment.Driver element 20 can be made up of master driver 30 and switching circuit 40; Master driver 30 comprises the first driving input Drv_In_1, second and drives input Drv_In_2, the 3rd to drive input Drv_In_3, four-wheel drive input Drv_In_4, the first drive output Drv_Out_1, the second drive output Drv_Out_2, the 3rd drive output Drv_Out_3 and four-wheel drive output Drv_Out_4.
First drives input Drv_In_1, second to drive, and input Drv_In_2, the 3rd drives input Drv_In_3, four-wheel drive input Drv_In_4 is connected and in order to the driving signal input DrvI as driver element 20.
Switching circuit 40 comprises the first switch input terminal Sw_In_1, second switch input Sw_In_2, the 3rd switch input terminal Sw_In_3, the 4th switch input terminal Sw_In_4, the first switch activation end Sw_1_En, second switch activation end Sw_2_En, the 3rd switch activation end Sw_3_En, the 4th switch activation end Sw_4_En, the first output switching terminal Sw_Out_1, second switch output Sw_Out_2, the 3rd output switching terminal Sw_Out_3 and the 4th output switching terminal Sw_Out_4.
First switch input terminal Sw_In_1, second switch input Sw_In_2, the 3rd switch input terminal Sw_In_3 and the 4th switch input terminal Sw_In_4 are electrically connected on the first drive output Drv_Out_1, the second drive output Drv_Out_2, the 3rd drive output Drv_Out_3 and four-wheel drive output Drv_Out_4 respectively.
First switch activation end Sw_1_En is electrically connected on an enable signal, and remains on the state be enabled at any time; Second switch activation end Sw_2_En, the 3rd switch activation end Sw_3_En and the 4th switch activation end Sw_4_En are respectively in order to as the first control signal input Cntl2, the second control signal input Cntl3 of driver element 20 and the 3rd control signal input Cntl4.
First output switching terminal Sw_Out_1, second switch output Sw_Out_2, the 3rd output switching terminal Sw_Out_3 and the 4th output switching terminal Sw_Out_4 are in order to as the first output Out1, the second output Out2 of driver element 20, the 3rd output Out3 and the 4th output Out4.
Fig. 5 a to Fig. 5 c is depicted as driver element 20 and can supplies and the arbitrary signal processing unit 1 matched combined synchronous rectifier control circuit of the present utility model shown in Fig. 4 a to Fig. 4 c, and its line connection is same as above, does not repeat them here; And the synchronous rectifier control circuit of any one combination can the operating state (cut-off state as previously described and following state) of each power switch in control switch module, effectively to reduce the switch cost of synchronous rectifier when underloading.
Certainly; the utility model also can have other various embodiments; when not deviating from the utility model spirit and essence thereof; those of ordinary skill in the art are when making various corresponding change and distortion according to the utility model, but these change accordingly and are out of shape the protection range that all should belong to the claim appended by the utility model.
Claims (9)
1. a synchronous rectifier control circuit, be applicable to a synchronous rectifier of control one power supply changeover device, this synchronous rectifier is electrically connected on the secondary winding of a transformer of this power supply changeover device and comprises multiple switch module, respectively this switch module comprises multiple power switch, it is characterized in that, this synchronous rectifier control circuit comprises:
One output current of the secondary winding of one this transformer of sensing, and the signal processing unit operating in the quantity of following state of the plurality of power switch is determined in this output current, be electrically connected on the secondary winding of this transformer; And
Multiple driver element, is electrically connected on the plurality of switch module and this signal processing unit respectively,
Wherein, when this output current is less than first predetermined value, one of them power switch in the plurality of switch module operates in following state, when this output current is greater than second predetermined value, the plurality of power switch all operates in following state, this output current is when this first predetermined value and this second predetermined value, and this signal processing unit increases along with this output current and increases the quantity operating in the power switch of following state.
2. synchronous rectifier control circuit as claimed in claim 1, it is characterized in that, this signal processing unit comprises a current sense end, multiple drive singal output and multiple control signal output, this current sense end is electrically connected on the secondary winding of this transformer, respectively this driver element comprises a driving signal input, multiple control signal input and multiple output, the plurality of drive singal output of this signal processing unit is electrically connected on the plurality of driving signal input of the plurality of driver element, the plurality of control signal output of this signal processing unit is electrically connected on this control signal input of the plurality of driver element, respectively the plurality of output of this driver element is electrically connected on one of them power switch respectively.
3. synchronous rectifier control circuit as claimed in claim 2, it is characterized in that, respectively the quantity of the plurality of control signal input of this driver element is P, and respectively the quantity of the plurality of output of this driver element is Q, and it meets following condition:
P＝Q-1。
4. synchronous rectifier control circuit as claimed in claim 2, it is characterized in that, this signal processing unit comprises a signal processor and a pulse width modulation controller, this signal processor comprises this current sense end and the plurality of control signal output, and this pulse width modulation controller comprises the plurality of drive singal output.
5. synchronous rectifier control circuit as claimed in claim 2, it is characterized in that, this signal processing unit comprises a signal processor and a switching device, this signal processor comprises this current sense end, the plurality of control signal output, one activation end, one switches control end and multiple operation mode signals output, this switch unit comprises the plurality of drive singal output, one activation end, one switches control end and multiple driving selecting side, this activation end of this signal processor and this switching controls end are electrically connected on this activation end and the switching controls end of this switching device respectively, the plurality of operation mode signals output of this signal processor is electrically connected on the plurality of driving selecting side of this switch unit respectively.
6. the synchronous rectifier control circuit as described in claim 4 or 5, it is characterized in that, this driver element comprises a master driver and secondary driver, this master driver and this driver comprise one first respectively and drive input, one second drives input, one first control end, one second control end, one first drive output and one second drive output, this of this master driver and this driver first drives input and second to drive input to be connected and is this driving signal input of this driver element, this second control end of this master driver is the first control signal input of this driver element, this first control end of this driver is this second control signal input of this driver element, this second control end of this driver is the 3rd control signal input of this driver element.
7. the synchronous rectifier control circuit as described in claim 4 or 5, it is characterized in that, this driver element comprises a master driver and secondary driver, and this master driver comprises one first and drives input and one first drive output, and this driver comprises one first and drive input, second drives input, one the 3rd drives input, one four-wheel drive input, one first control end, one second control end, one the 3rd control end, one the 4th control end, one first drive output, one second drive output, one the 3rd drive output and a four-wheel drive output, this first driving input of this master driver, this the first driving input of this driver, this second drives input and the 3rd to drive input to be connected and is this driving signal input of this driver element, this first control end of this driver, this second control end and the 3rd control end are respectively this first control signal input of this driver element, this the second control signal input and the 3rd control signal input.
8. the synchronous rectifier control circuit as described in claim 4 or 5, is characterized in that, this driver element comprises a master driver and a switching circuit, and this master driver comprises one first and drives input, one second drives input, one the 3rd drives input, one four-wheel drive input, one first drive output, one second drive output, one the 3rd drive output and one the 4th four-wheel drive output, this first driving input, this the second driving input, 3rd drives input and this four-wheel drive input to be connected and is this driving signal input of this driver element, and this switching circuit comprises one first switch input terminal, one second switch input, one the 3rd switch input terminal, one the 4th switch input terminal, one first switch activation end, one second switch activation end, one the 3rd switch activation end, one the 4th switch activation end, one first output switching terminal, one second switch output, one the 3rd output switching terminal and one the 4th output switching terminal, this first to fourth switch input terminal of this switching circuit is electrically connected on this first to fourth drive output of this master driver respectively, this second to the 4th switch activation end of this switching circuit is respectively this second to the 4th control signal input of this driver element, and this first to fourth output switching terminal of this switching circuit is this first to fourth output of this driver element.
9. synchronous rectifier control circuit as claimed in claim 1, it is characterized in that, the plurality of quantity of the plurality of power switch operating in following state is directly proportional to the size of this output current.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105991048A (en) * | 2015-03-04 | 2016-10-05 | 群光电能科技股份有限公司 | Synchronous rectifier control circuit and control method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105991048A (en) * | 2015-03-04 | 2016-10-05 | 群光电能科技股份有限公司 | Synchronous rectifier control circuit and control method thereof |
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