Micrel, Incorporated

Maxim Integrated Products, Inc.

William MacLean

Dashun Xue

Leland Swanson

Bruce C Larson

A buck switching regulator implements a fixed frequency feedback control circuit including a voltage control loop and a frequency control loop to regulate the switching frequency of the buck switching regulator to a fixed or nearly fixed frequency. The voltage control loop, implementing ripple mode control, is configured to control the power switches in response to the switching regulator output voltage or a signal related to the switching regulator output voltage. The frequency control loop, implementing a phase-locked loop control scheme, is configured to adjust the on-time of the high-side switch so as to regulate the switching frequency to be equal to or be proportional to the reference frequency.

Buck DC-DC converter with fixed frequency

A buck switching regulator includes a feedback control circuit using a four-input comparator to regulate the output voltage to a substantially constant level with reduced voltage offset and with fast transient response. In some embodiments, the buck switching regulator uses the four-input comparator to compare a first feedback signal without ripple and a second feedback signal with injected ripple components to a reference level. The four-input comparator generates an output signal to control the switching of the power switches. The buck switching regulator generates an output voltage with increased accuracy and fast transient response. Furthermore, the buck switching regulator can be used with output capacitor having any value of ESR.

Hysteretic buck DC-DC converter

A buck switching regulator includes a feedback control circuit including a first gain circuit generating a first feedback signal indicative of the regulated output voltage; a ripple generation circuit generating a ripple signal that is injected to the first feedback signal; and a comparator receiving a first reference signal and the first feedback signal to generate a comparator output signal. The switching regulator further includes an offset compensation circuit including a second gain circuit generating a second feedback signal indicative of the regulated output voltage; and an operational transconductance amplifier (OTA) configured to receive the second feedback signal and the first reference signal and to generate an output signal. The output signal of the OTA is coupled to the comparator to adjust an offset to the comparator so as to cancel the offset at the regulated output voltage due to the injected ripple signal.

Buck DC-DC converter with accuracy enhancement

A buck switching regulator includes a feedback control circuit including a feedback network including first and second gain circuits configured to generate first and second feedback signals, respectively, indicative of the regulated output voltage; a ripple generation circuit configured to inject a ripple signal to the first gain circuit; an operational transconductance amplifier (OTA) configured to receive the second feedback signal and a reference signal and to generate an output signal being coupled to the first gain circuit to adjust the first feedback signal; and a comparator configured to receive the first feedback signal and the reference signal and to generate a comparator output signal. The output signal of the OTA is applied to the first feedback signal to cancel a voltage offset in the regulated output voltage due to the injected ripple signal to the first gain circuit.

Buck DC-DC converter with improved accuracy

A system, method and apparatus is provided for pulse width correction in a power driver. In an embodiment, an apparatus includes an operational amplifier having an input and an output. The input of the operational amplifier is coupled to receive an input pulse signal. The apparatus further includes an output stage having an input coupled to the output of the operational amplifier. The output stage also includes a current output configured to couple to a load and to a voltage sense output. The apparatus also includes a comparator having an inverting input coupled to the voltage sense output of the output stage, a non-inverting input configured to couple to an input signal, and an output. Also, the apparatus includes a timing circuit with an input coupled to the output of the comparator and an input coupled to the input signal. The timing circuit also has an output to supply the input pulse signal. The timing circuit measures a delay from a change in the input signal to a change in the output of the comparator. The timing circuit replicates the measured delay as a delay in a change to the input pulse signal.

Growing community of inventors

Austin, TX, United States of America

William MacLean