| 摘要 |
<p>A circuit for driving an electrical load such as an electric motor, by a pulse width modulated current includes a saturable current driver connected to the load. The circuit includes a linear transconductance amplifier with currentsensing feedback for applying a pulse-width modulated control current to the driver. The feedback preserves the extent of saturation and of cut-off by providing current pulses which are invariant with respect to thermally induced changes in circuit parameters. Amplitude and offset control circuitry are also provided for setting the range of current values during the current pulsing to optimize the operation of the driver. In an alternative simplified circuit, a low-level switching circuit drives complementary output transistors operating in a linear fashion, and producing current pulses which are invariant with respect to the saturable driver parameters.</p> |
