Mosfet High Side Switch Design

In this instance the mosfet switch is connected between the load and the positive supply rail high side switching as we do with pnp transistors.

Mosfet high side switch design.

A high side p channel mosfet and a low side n channel mosfet tied with common drains figure 5 make a superb high current ªcmos equivalentº switch. For an n channel mosfet the source connects to ground and the drain connects to the negative side of the load. The n channel mosfet of a buck converter is a high side switch. Ir2110 is a high low side gate driver ic which is used with power mosfet and igbt.

In a p channel device the conventional flow of drain current is in the negative direction so a negative gate source voltage is applied to switch the transistor on. With adjustable current limit high accuracy current sense and a wide range of rdsons our smart high side switches provide the optimal solution for your specific use case. The opposite of the low side switch is the high side switch. With our switch portfolio you can find a protection solution for your inductive capacitive and resistive loads ensuring your design is scalable and robust.

To switch 0v. The mosfet were used as high side switches in the circuit. N channel p channel 15. It worked but when i started to draw more than a few ma of current the voltage starts to sag towards 4v and even lower.

It s a simple circuit that has a input for positive and negative and an output for positive and negative connections. Here s my schematic and board design for a simple high side switch using a p channel mosfet. While you can use a jfet for this circuit an enhancement mode mosfet works better. A mosfet only requires gate current during the switching edge to charge the gs capacitance.

For driving the mosfet in high side configuration ir2110 gate driver ic was used. This transistor connects between v and the load. Use a n channel mosfet with source connected to 0v either directly or via a current limiting resistor and the load connected to drain. One fault common to such circuits has been the excessive crossover current during switching that may occur if the gate drive allows both mosfets to be on simultaneously.

I started with this circuit by jon watte for using a p channel mosfet as a high side switch for 12v. Drive circuits for the high side switches are called high side drivers and are more complicated than low side drivers because of the required voltage translation to the supply and because it is more difficult to turn off a floating switch. While designing the ups circuits mosfet were used in the inverter circuits. This gate current can be high.