| 摘要 |
A circuit and method for controlling the amplitude and direction of load current in a bidirectional direct current control bridge of the type having four bridge arms, each such arm having an electronic switching element electrically disposed therein, and a load, illustratively an ohmic-inductive load, connected to the junctures of said bridge arms. Load current is conducted to the load by applying energizing pulses to each of the switching elements in a pair of diagonally disposed bridge arms, the respective pulse energizing signals being out of phase with respect to one another. Load current is responsive to the duration of the interval during which the switching elements in the diagonal pair of bridge arms are simultaneously conductive. Circuitry is provided for pulse energizing the electronic switching elements in the second diagonal pair of bridge arms, while inhibiting conduction of the pulse energizing signals to the first diagonal pair, in response to a change in polarity of a control signal. The amplitude of the control signal governs the pulse-width ratio of the pulse energizing signals, and therefore, the duration of the intervals of simultaneous conduction of the switching elements in the diagonal pair. Circuitry is provided for inhibiting the conduction of all pulse energizing signals for a predetermined interval of time in response to the change of polarity of the control signal. |
