Patent attributes
A vertical insulated gate field effect power transistor (3) has a plurality of parallel transistor cells (TC3) with a peripheral gate structure (G31, G2) at the boundary between each two transistor cells (TC3). The gate structure (G31, G32) comprises first (G31) and second (G32) gates isolated from each other so as to be independently operable. The first gate (G31) is a trench-gate (21, 22), and the second gate (G32) has at least an insulated planar gate portion (13, 14). Simultaneous operation of the first (G31) and second (G32) gates forms a conduction channel (23c, 23b) between source (16) and drain (12) regions of the device (3). The device (3) has on-state resistance approaching that of a trench-gate device, better switching performance than a DMOS device, and a better safe operating area than a trench-gate device. The device (3) may be a high side power transistor is series with a low side power transistor (6) in a circuit arrangement (50) (FIG. 14) for supplying a regulated output voltage. The device (3) may also be a switch in a circuit arrangement (60) (FIG. 15) for supplying current to a load (L). These circuit arrangements (50, 60) include a terminal (Vcc, VF) for applying a supplied fixed potential to an electrode (G311) for the first gates (G31) and a gate driver circuit (573, 673) for applying modulating potential to an electrode (G321) for the second gates (G32).
