Circuit designers must have considered a question when choosing MOSFETs: Should they choose P-channel MOSFET or N-channel MOSFET? As a manufacturer, you must want your products to compete with other merchants at lower prices, and you also need to make repeated comparisons. So how to choose? OLUKEY, a MOSFET manufacturer with 20 years of experience, would like to share with you.
Difference 1: conduction characteristics
The characteristics of N-channel MOS are that it will turn on when Vgs is greater than a certain value. It is suitable for use when the source is grounded (low-end drive), as long as the gate voltage reaches 4V or 10V. As for the characteristics of P-channel MOS, it will turn on when Vgs is less than a certain value, which is suitable for situations when the source is connected to VCC (high-end drive).
Difference 2: MOSFET switching loss
Whether it is N-channel MOS or P-channel MOS, there is an on-resistance after it is turned on, so the current will consume energy on this resistance. This part of the energy consumed is called conduction loss. Choosing a MOSFET with a small on-resistance will reduce the conduction loss, and the on-resistance of current low-power MOSFETs is generally around tens of milliohms, and there are also several milliohms. In addition, when MOS is turned on and off, it must not be completed instantly. There is a decreasing process, and the flowing current also has an increasing process.
During this period, the MOSFET's loss is the product of voltage and current, called switching loss. Usually switching losses are much larger than conduction losses, and the higher the switching frequency, the greater the losses. The product of the voltage and current at the moment of conduction is very large, and the loss caused is also very large, so shortening the switching time reduces the loss during each conduction; reducing the switching frequency can reduce the number of switches per unit time.
Difference three: MOSFET use
The hole mobility of P-channel MOSFET is low, so when the geometric size of the MOSFET and the absolute value of the operating voltage are equal, the transconductance of P-channel MOSFET is smaller than that of N-channel MOSFET. In addition, the absolute value of the threshold voltage of P-channel MOSFET is relatively high, requiring a higher operating voltage. P-channel MOS has a large logic swing, a long charging and discharging process, and a small device transconductance, so its operating speed is lower. After the emergence of N-channel MOSFET, most of them have been replaced by N-channel MOSFET. However, because P-channel MOSFET has a simple process and is cheap, some medium- and small-scale digital control circuits still use PMOS circuit technology.
Okay, that’s all for today’s sharing from OLUKEY, a packaging MOSFET manufacturer. For more information, you can find us on the OLUKEY official website. OLUKEY has focused on MOSFET for 20 years and is headquartered in Shenzhen, Guangdong Province, China. Mainly engaged in high current field effect transistors, high power MOSFETs, large package MOSFETs, small voltage MOSFETs, small package MOSFETs, small current MOSFETs, MOS field effect tubes, packaged MOSFETs, power MOS, MOSFET packages, original MOSFETs, packaged MOSFETs, etc. The main agent product is WINSOK.
Post time: Dec-17-2023
