| 摘要 |
A switching controller or regulator (implemented as an integrated circuit) which is operable in any selected one of multiple two modes, including an oscillator mode in which it generates switch control signals for turning on a power switch in response to internally generated clock pulses, a sync mode in which it generates the switch control signals in response to pulses supplied from external circuitry, and preferably also a shutdown mode in which it consumes little or no power and does not generate switch control signals. In the oscillator and sync modes, the controller or regulator also generates additional control signals for turning off the power switch each time after it is turned on, so as to regulate the duty cycle of the power switch. Preferably, the controller or regulator chip has only a single external pin for receiving control signals for causing the chip to enter a sequence of the available operating modes, and it includes a level shifter, a sync timer, a shutdown timer, and a controllable oscillator, all connected to such pin. A multiplexer, operating under control of the sync timer, receives the outputs of the level shifter and oscillator, and selects one of these outputs in response to a control signal from the sync timer. Other aspects of the invention are a DC-to-DC converter including a switching controller or regulator chip of the described type and circuitry external to the chip for generating a regulated output potential in response to an input potential, and a method for performing DC-to-DC conversion using any embodiment of the switching controller or regulator chip.
|
