| 摘要 |
In a buck-boost, switching regulator, separate signals are developed to control duty cycles of regulator switches. Control exercised by a pair of feedback-determined reference signal voltages through which a ramp signal is swept at inputs of separate comparators, comparator outputs control respective switches. A predetermined maximum voltage difference is permitted between the reference signal voltages. The reference used to control switching of one end of the regulator inductance is limited to a minimum voltage corresponding to a minimum duty cycle greater than 0% while the other reference is used to control the other end of that inductance and is limited to a maximum voltage corresponding to a minimum duty cycle less than 100%. A current limiting feedback from one of the switches is operated in response to current in excess of a predetermined level to force the ramp signal to a level corresponding to 0% duty cycle for both switches at the same time.
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