| 摘要 |
The present invention provides a self-driven LDMOS which utilizes a parasitic resistor between a drain terminal and an auxiliary region. The parasitic resistor is formed between two depletion boundaries in a quasi-linked deep N-type well. When the two depletion boundaries pinch off, a gate-voltage potential at a gate terminal is clipped at a drain-voltage potential at said drain terminal. Since the gate-voltage potential is designed to be equal to or higher than a start-threshold voltage, the LDMOS is turned on accordingly. Besides, no additional die space and masking process are needed to manufacture the parasitic resistor. Furthermore, the parasitic resistor of the present invention does not lower the breakdown voltage and the operating speed of the LDMOS. In addition, when the two depletion boundaries pinch off, the gate-voltage potential does not vary in response to an increment of the drain-voltage potential.
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