LT8672 is controller of an active commutator, this parts of an apparatus (power source can is to offer protection of retrorse electric current and commutate in car environment with a MOSFET) . On the tradition, this job is by a Xiaoteji diode is assumed finish, under photograph comparing, the active protection of LT8672 has a few advantages:

 

The power comsumption with few *

* is small, but prescient, steady 20mV voltage drop

* is additional, LT8672 still has the characteristic that course of the many power source in aiming to satisfy car environment asks:

* inputs protection reversely to –40V

Limits of work of * wide input: 3V comes 42V

* exceeds swift transient state to answer

* commutate 6VP-P, be as high as 50kHz; Rectification 2VP-P, be as high as 100kHz

What * uses at FET driver is compositive the excel of character of service that changes step up manostat charges pump parts of an apparatus

 

Graph 1 show gave a complete protective solution.

 

Answer of rectification quickly to inputting ripple

 

Car standard (ISO 16750 or LV124) regulation, car electron control is unit (ECU) can accept to have be as high as 6VP-P (to be in be as high as 30kHz frequency to fall) the power source of overlay AC ripple. The grid driver that LT8672 uses at controlling exterior MOSFET is enough and powerful, can handle the ripple frequency that is as high as 100kHz, thereby utmost reduced retrorse electric current. Graph 2 show an example that gave commutate of ripple of this kind of AC.

 

 

When using the setting that the graph shows 3 times, the function bear that LT8672 (uses IPD100N06S4-03 to serve as exterior MOSFET) and diode of a Xiao Te radical (CSHD10-45L) is about the same. Here, be located in an input to carry the power source of a 12V on to be used at imitating car voltage source, and output end bore the weight of of a 10A constant electric current. Graph 4 show the hot performance that gave these two kinds of solutions to fall in stable state circumstance. When taking cooling step, the hot property Yuan Shengyi of LT8672 solution prepares, achieved peak value temperature is 36°C only, and the peak value temperature of solution of diode of Xiao Te radical is gotten high much, achieved 95.1°C.

 

 

 

Car task key circuit must the case can be launched in cold car next moving, meeting pelter reachs right now car batteries voltage 3.2V. Considering this, products of a lot of car class electron are become by the design can be in low the job below the condition that inputs to 3V. Of diode of Xiao Te radical can bringing an issue during cold car is started to voltage drop changeably, right now this pressing falls generation a 2.5V comes the downstream voltage of 3V, this to some systems move and talk is too small. By comparison, the 20mV voltage drop that LT8672 solution stabilizes by right of its assured needs 3V, simplified to circuit is designed and improve systematic consistence thereby.

 

Fall when VBATT to 3.2V when, LT8672 control system (A) maintains VIN>3V, make LT8650S can maintain his to output VSYS to stabilize consequently in 1.8V, and in Xiaoteji diode system (in B) , the input voltage VIN of LT8650S falls to under its voltage of the least job, make it cannot maintain 1.8V on its output VSYS so.

 

 

A lot of replacing model active commutator controller is used charge pump is grid driver power supply. These solutions cannot offer powerful grid charging current and a stable output voltage normally, limitted the frequency limits of successive commutate and function consequently. Of LT8672 compositive the grid driver voltage that changes step up manostat to be able to offer a tight adjustment and powerful grid driver electric current.

 

 

LT8672 can undertake rectification to the ripple of high frequency AC on car power source. This parts of an apparatus uses compositive change step up manostat with drive a MOSFET, exceed swift transient state to answer in the implementation in successive commutate process thereby, this is opposite at charging pump the solution is improve. LT8672 uses the dainty 10 MSOP that cite a base to enclose, its have rectification and retrorse input protection function and low power comsumption exceed wide working range with (this is started to cold car is very desirable) .