CN206117488U - Synchronous Rectifier control driver - Google Patents

Abstract

The utility model discloses a synchronous Rectifier control driver, prior art be not bulky with high costs be exactly that the loss increases, especially difficult the giving of the value of resistance is compromise under the condition that rectified current differed great. The utility model discloses a first diode D1, second diode D2, third diode D3, first resistance R1, second resistance R2, third resistance R3, fourth resistance R0, the 5th resistance rg, comparator U, synchronous Rectifier pipe Q1, the 2nd synchronous Rectifier pipe Q2 and synchronous Rectifier MOSFET, the utility model discloses both realized the synchronous Rectifier pipe and closed phase reverse voltage and reliably block, realized that synchronous Rectifier managed the direction of current flow's high -speed, accurate sampling, closed -loop control, a driven body structure of surveying simultaneously again.

Description

Synchronous rectification controls driver

Technical field

The utility model is related to a kind of synchronous rectification of power conversion technical field, especially a kind of energy high speed, standard Really detect the synchronous drive control device of the synchronous rectifier sense of current.

Background technology

Conventional rectification diode is substituted using MOSFET pipes and realizes synchronous rectification, be greatly improved the overall effect of converter Rate, this technology has become the new technology that whole power supply industry is widely popularized.The research and development heat of power technology is always between last decade Point, the know-why of a maturation but causes whole industry specialists, scholar to join in research and development for many years, and how it main reason is that It is allowed to be common to the different conduction mode of different supply convertor topological sums.Can obtain from the working condition of commutation diode Know, it can not only rectification and also can afterflow, the Synchronization Control point for really meeting commutation diode moving law should be commutating circuit Sense of current transfer point.Therefore, current mode is synchronously only optimal synchronization, to detect the electric current reversal point master of commutating circuit There are two kinds of ways：1. current transformer is adopted；2. inspection leakage resistance is sealed in.But both schemes cut both ways, the former volume Big high cost；The latter's loss is increased, and especially in the case where rectified current difference is larger, the value difficulty of resistance is given and being taken into account.It is newest Technology be then directly using synchronous rectification MOSFET pipe conducting internal resistance substitute inspection leakage resistance, this technology can obtain most succinct Circuit and minimum loss.Traditional voltage or current synchronization detection mostly is electric resistance partial pressure type, in synchronous rectifier closed-down period Between input of sampling will bear the impact compared with high backward voltage, using the sampling resistor of larger value and clamp circuit need to be set dropping Low-loss, so can cause the decline of response speed again.Newest technology is to seal in a diode in sampling end to block instead To voltage, this really good method.However, due to diode forward conduction voltage drop by batch property difference affected and with Environment temperature and the inherent characteristic that changes, are greatly lowered all can control accuracy and reliability of operation.Especially using super Problem is more projected during the synchronous rectifier of low conducting internal resistance.

The content of the invention

The utility model is directed to the deficiencies in the prior art, it is proposed that one kind had both realized synchronization using a pair of duo-diodes Rectifying tube closed-down period backward voltage reliably blocks, while and realizing the high speed of the synchronous rectifier sense of current, precision detection Sampling, closed-loop control, the integrative-structure for driving.

The utility model be a kind of synchronous rectification control driver, including the first diode D1, the second diode D2, the 3rd Diode D3, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R0, the 5th resistance Rg, comparator U, first Synchronous rectification driving tube Q1 and the second synchronous rectification driving tube Q2；

The first described diode D1 negative electrodes connect the source electrode of external sync rectification MOSFET, and anode and the 3rd diode D3 are positive Pole, one end of first resistor R1, one end of 3rd resistor R3, comparator U input in the same direction connection, first resistor R1 it is another Hold and be connected with one end of one end of electric capacity CO, one end of second resistance R2, the positive power source terminal of comparator U, the 4th resistance R0, electric capacity The drain electrode of another termination external sync rectification MOSFET pipes of CO, the other end of second resistance R2 and the reverse input of comparator U End, the anode connection of the negative electrode of the 3rd diode D3, the second diode D2, the negative electrode of the second diode D2 is negative with comparator U Power end, the colelctor electrode of the second synchronous rectification driving tube Q2 connect and connect the drain electrode of external sync rectification MOSFET pipes, and the 3rd is electric The other end and the base stage of the second synchronous rectification driving tube Q2 of resistance R3, the base stage of the first synchronous rectification driving tube Q1, comparator U Output end connects, and the other end of the 4th resistance R0 is connected and connects VCC with the colelctor electrode of the first synchronous rectification driving tube Q1, and first is same Step rectification driving tube Q1 emitter stages are connected with the emitter stage of the second synchronous rectification driving tube Q2, one end of the 5th resistance Rg, and the 5th The grid of another termination external sync rectification MOSFET pipes of resistance Rg.

Beneficial effect：

1st, on the basis of the technology is respectively provided with two inputs of high speed voltage comparator and end is compared in sampling, its electricity Bit value is determined that optimal way is using a pair twin two poles by the forward bias point current potential of two diodes of high degree of symmetry Pipe.The two diodes are respectively by equivalent resistance from same positive supply to apply to obtain temperature each other by forward current is biased Degree compensation and two minimum bias voltages of pressure reduction, once " zero " point of the two bias voltages is set up respectively in synchronous rectification The source of pipe, leakage two ends, you can flowed through the pressure drop that the electric current of raceway groove internal resistance is formed, including the voltage such as size of current and direction Information is converted directly into two inputs of comparator, and such circuit structure not only greatly increases the precision and base of sampling Originally impact of the environment temperature to reliability is eliminated；

2nd, close the initial stage in synchronous rectifier, the diode in sampling end can be become just, by low change with backward voltage by negative High process gradually reduces diode bias current, until when backward voltage rises above the supply voltage of controller, two Pole pipe just enters reverse blocking.Therefore, the level meeting high jump of comparator sampling input is input into common mode electricity to supply voltage to having The comparator that pressure scope is limited is infeasible, even if avoiding damaging device using the comparator of track to track, equally There is comparator input terminal because excessive voltage swing can cause control response to slow.The technology is defeated in comparator two Enter to be provided between end a Schottky diode and to realize this jumping-up voltage conducting clamper, limit sampling end voltage swing Within 0.2V, the response speed of controller is effectively improved；

3rd, the technology employs the high-precision high-speed comparator with low offset current, even if using as little as a few millis of internal resistance The MOS synchronous rectifiers in Europe will not also produce the malfunction of Synchronization Control；

4th, concussion is produced in state transition point to eliminate high-speed comparator, the technology is especially provided with closed loop positive feedback, Microly positive and negative feedthrough voltage is added in the way of to change reference edge diode bias current, effectively eliminate harmful shake Swing.

Description of the drawings

Fig. 1 is structural representation of the present utility model.

Specific embodiment

As shown in figure 1, a kind of synchronous rectification of the utility model controls driver, including the first diode D1, the two or two pole Pipe D2, the 3rd diode D3, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R0, the 5th resistance Rg, compare Device U, the first synchronous rectifier Q1, the second synchronous rectifier Q2 and synchronous rectification MOSFET；First synchronous rectification driving tube Q1, Two synchronous rectification driving tube Q2 collectively constitute the synchronous rectification MOSFET pipe outside totem driving；

The first described diode D1 negative electrodes meet the source electrode of external sync rectification MOSFET pipes, anode and the 3rd diode D3 Anode, one end of first resistor R1, one end of 3rd resistor R3, comparator U input in the same direction connection, first resistor R1 it is another One end of one end and electric capacity CO, one end of second resistance R2, the positive power source terminal of comparator U, one end of the 4th resistance R0 are connected, electricity Hold the drain electrode of another termination external sync rectification MOSFET pipes of CO, the other end of second resistance R2 is reverse defeated with comparator U Enter the anode connection of end, the negative electrode of the 3rd diode D3, the second diode D2, the negative electrode of the second diode D2 is with comparator U's Negative power end, the second synchronous rectification driving tube Q2 colelctor electrodes connect and connect the drain electrode of external sync rectification MOSFET pipes, and the 3rd is electric The other end of resistance R3 and base stage, the base stage of the first synchronous rectifier Q1, the output of comparator U of the second synchronous rectification driving tube Q2 End connection, the other end of the 4th resistance R0 is connected and connects VCC with the colelctor electrode of the first synchronous rectification driving tube Q1, and first is synchronous whole Stream driving tube Q1 emitter stages are connected with the emitter stage of the second synchronous rectification driving tube Q2, one end of the 5th resistance Rg, the 5th resistance The grid of another termination external sync rectification MOSFET pipes of Rg.

It is with a high speed voltage comparator as control core that the utility model synchronous rectification controls driver；Driver is A totem is pushed directly on by the output end of comparator to be formed；The detection of the external sync rectifying tube sense of current is symmetrical by two Resistance and Diode series branch road, the equivalent resistance of each route provides forward bias for diode, and this is biased The two diode forward pressure drops set up are respectively connected to the in the same direction and reverse input end of comparator, the bias current of two branch roads Outflow end is respectively connected to the source electrode of external sync rectification MOSFET and drain electrode two ends, and such symmetrical level translation branch road can The pressure drop that the electric current and its polarity of outside MOSFET sources-leakage raceway groove internal resistance are formed is flowed through, comparator two is critically converted to The sampled signal of input, in current polarity switching instant, several millivolts of change just can be recognized accurately.

Synchronous rectification control contains positive feedback closed loop, and the output for being connected to comparator by feedback resistance R3 is defeated with the same direction Enter between end；Both electric initial output had been realized to close preferentially, concussion during State Transferring can have effectively been eliminated again；

Described synchronous rectification controls the response speed that control can be effectively improved containing a sampling input clamp diode；

The twin double diode that described synchronous detection is adopted can also adopt two with batch and detect its identical biasing Forward voltage error under current condition<Single diode of 5mV, heat-insulated sealing is added after attachment in its top surface, is in them In relative isothermal body, equally can obtain with twin to managing close using effect.

Claims (1)

1. synchronous rectification controls driver, including the first diode D1, the second diode D2, the 3rd diode D3, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R0, the 5th resistance Rg, comparator U, the first synchronous rectification driving tube Q1 and Second synchronous rectification driving tube Q2；

It is characterized in that：The first described diode D1 negative electrodes connect the source electrode of external sync rectification MOSFET, anode and the three or two Pole pipe D3 anode, one end of first resistor R1, one end of 3rd resistor R3, the input in the same direction connection of comparator U, first resistor The other end of R1 and one end of electric capacity CO, one end of second resistance R2, the positive power source terminal of comparator U, one end of the 4th resistance R0 Connection, the drain electrode of another termination external sync rectification MOSFET pipes of electric capacity CO, the other end of second resistance R2 is with comparator U's Reverse input end, the negative electrode of the 3rd diode D3, the second diode D2 anode connection, the negative electrode of the second diode D2 with compare The negative power end of device U, the colelctor electrode of the second synchronous rectification driving tube Q2 connect and connect the drain electrode of external sync rectification MOSFET pipes, The base stage of the other end of 3rd resistor R3 and the second synchronous rectification driving tube Q2, the base stage of the first synchronous rectification driving tube Q1, ratio Output end connection compared with device U, the other end of the 4th resistance R0 is connected and connects with the colelctor electrode of the first synchronous rectification driving tube Q1 Emitter stage, one end of the 5th resistance Rg of VCC, the first synchronous rectification driving tube Q1 emitter stages and the second synchronous rectification driving tube Q2 Connection, the grid of another termination external sync rectification MOSFET pipes of the 5th resistance Rg.