Some application situation needs to use a heat to insert pulls out the controller, a circuit breaker or both must use, adapts the bipolarity cocurrent input power source skeleton line. In certain uses inserts hotly pulls out in controller’s situation, this kind of request stems from merely to the initial firing current consideration. Must eliminate coupling’s stress and the power source skeleton line disturbance, must control the initial firing current. Moreover when some application situation in some power source some kind of reason breaks down will have the problem. The gallium arsenic FET amplifier’s bias power source is a model. If you remove negative electronics grid bias, then you must remove the drain electrode power source; Otherwise, the amplifier because of the drain electrode electric current will be oversized, but will destroy voluntarily. But so long as you use one to pass the dowtherm to insert the controller only, may satisfy the above these two requests.
Figure 1 this electric circuit is the low tension circuit uses the bipolarity voltage sequencer.
Figure 1, shows the electric circuit relocatable mode to use TPS2331 (i.e. IC1). This electric circuit enables IC the earth to concern with negative input voltage.
If the skeleton line voltage is too low or negative skeleton line voltage is too high, then this electric circuit cannot achieve 1.225V on the VSENSE pin the threshold value, therefore IC shutdown. On the VSENSE pin has approximately the 30mV lag voltage, guarantees when the IC opening not trembles.
When the positive and negative two voltages surpass the respective threshold value, IC1 puts through, is two FET provides the slewing rate which controls along with the time linearity is grown. What must pay attention, this electric circuit only uses N trench FET, because the size and the expense assign in the situation, N trench FET breakover resistance ratio P trench FET must be small. In order to cause the Q1A breakover, TPS2331 has an integral electric charge pump, it can produce one compared to the skeleton line voltage great voltage, thus plays the enhancement role to this FET. Along with grid bias’s establishment, Q3 plays the linear level transistor’s role, thus Q1B can also grow along with the time linearity, its breakover speed is the TPS2331 14μA output current and the C3 value function. This design uses these two FET the basis is the biggest resistance which and the FET power loss value in the direct-current circuit permits. In fact may use any specification FET, regards you to want the control the electric current size to decide. What must pay attention, adds to TPS2331 the total voltage scope not to be able to surpass the most large quantity to decide voltage 15V. If IC1 does not fluctuate between two input supply voltage, then negative input voltage is quite possibly big. Figure 2 showed this kind of kind of application electric circuit, its input voltage was 5V and - 12V. This electric circuit’s overriding demand is, level shifting transistor Q3 wants the ability the high voltage. In addition, this electric circuit can also use looks like the IC1 most large quantity to decide the voltage 15V that high input voltage.
Figure 2, this electric circuit, in shown in Figure 1 in the electric circuit foundation to have the modification, can withstand the high voltage.
