Patent ID: 7518349
Filing Date: 2009-04-14
Classification: H02M,Y02B

Abstract:
1. A voltage mode DC-DC converter for supplying a regulated DC output voltage to a load comprising: an output power switching stage having power switches coupled between an input voltage terminal to which an input voltage Vin is applied, and a reference voltage terminal, and having a common node therebetween coupled by way of an output inductor to an output node from which said regulated DC output voltage is supplied; a control circuit for controlling switching of said power switches for voltage mode operation of said DC-DC converter; and a pulse width modulation (PWM) voltage waveform generator circuit, which is operative to generate a PWM voltage waveform, in response to which said control circuit controls switching of said power switches, said PWM voltage waveform generator including a current multiplier/divider that is operative to provide feed-forward compensation for a periodic voltage waveform used to generate said PWM voltage waveform, such that said periodic voltage waveform has a peak-to-peak amplitude Vpp that is proportional to said input voltage Vin, wherein said PWM voltage waveform generator circuit is operative to generate said periodic voltage waveform in accordance with an output current produced by said current multiplier/divider, and includes a first voltage-to-current converter stage that is operative to generate a first current Ivin representative of a voltage-divided fraction of said input voltage Vin, a second voltage-to-current converter stage that is operative to generate a second current Iosc derived from a stable voltage reference and a user-programmable circuit component that is used to define said frequency of said periodic voltage waveform, and a third voltage-to-current converter stage that is operative to generate a third, fixed current Iref, and wherein said current multiplier/divider is operative to produce said output current in accordance with a prescribed product/division of said first, second and third currents.