| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of components in a step-down type power supply means. SOLUTION: A load 41 is connected between both ends of a series circuit constituted of a DC power supply 1, an NMOS177, an internal diode 62 and so on. The gate of a NMOS14 is connected with the drain of an NMOS73, and the source of the NMOS14 is connected with the gate and the source of the NMOS73 and one end of a capacitor 4. The other end of the capacitor 4 is connected with the drain of an NMOS11, and three pairs of series circuits constituted of the NMOS14, the capacitor 4, and the NMOS11 are connected inparallel between both the ends. The internal diode of 'the NMOS173 connecting the gate and the source' and three 'series circuit constituted of the capacitor 4 and the NMOS73' are serially-connected between both the ends. 'A forward bias means is provided, which is constituted of NMOS168 to 170, a capacitor 18 and so on and biases the respective NMOS11 in the gate order, when the NMOS177 is off'. The gate drive means of the respective NMOS14 thus becomes simplified.
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