摘要:
A buck-boost converter circuit includes a mode selection circuit that asserts a buck enable signal if an input voltage is higher than a lower threshold, and asserts a boost enable signal if the input voltage is lower than an upper threshold. A control circuit asserts a buck PWM signal upon a pulse in a buck clock and de-asserts the buck PWM signal if a buck ramp is higher than a buck control signal, and it keeps the buck PWM signal asserted if the buck enable signal is de-asserted. The control circuit asserts a boost PWM signal upon a pulse in a boost clock and de-asserts the boost PWM signal if a boost ramp is higher than a boost control signal, and it keeps the boost PWM signal de-asserted if the boost enable signal is de-asserted.
摘要:
In a multi-phase power supply voltage regulator functioning at a nominal switching frequency, one or more phases are kept off for optimizing energy efficiency at relatively low load conditions. Reactivation of stand-by phases in response to a load increase transient is made more efficiently by exploiting information already present in the output voltage control loop. The technique comprises a) deriving from the control loop information on the equivalent nominal switching frequency given by the product of the nominal switching frequency by the number of active phases; b) updating at every beat of a clock signal the instantaneous value of the equivalent switching frequency; c) determining the band of equivalent switching frequency values to which the instantaneous value belongs; d) logically combining the equivalent switching frequency information with a determined band of output current level, for switching on one or more stand-by phases in response to a load increase transient.