| 摘要 |
PURPOSE:To obtain a power transistor driver having a small IC chip size with low power consumption, by providing a bipolar transistor TR and an MOS-FET on the same IC chip and making an MOS-FET a TR to supply power. CONSTITUTION:The output current of a differential amplifier consisting of bipolar TR1 and TR2 and a TR3 is converted into voltage signals by a P-channel MOS TR. The relationship between the drain current and the gate-source voltage of the MOS TR is decided by the width W and the length L of the gate. Then W/L is the larger, the larger drain current is obtained to the given gate- source voltage. Therefore no gate current is needed despite an increment of undesired current of an MOS TR27 by increasing the W/L of the TR27 compared with the W/L of an MOS TR26 and in response to a desired current. Thus only the size of the TR27 is increased to obtain a current required for driving a power TR9. As a result, the size can be reduced for TR1, TR2 and TR3 respectively. |
