Analog Devices,inc.

Brian P Erisman

Richard Redl

Jonathan Mark Audy

Gabor Reizik

A digital blanking circuit allows a first digital input signal transition to be passed on to a following stage, but prohibits the passing of subsequent transitions for a predetermined blanking interval. One embodiment of the present invention employs rising edge and falling edge latches, the inputs of which receive the digital input signal and the outputs of which are connected to a two-to-one multiplexer. The mux output is connected to a blanking interval circuit, which is triggered to begin timing a blanking interval by a multiplexer output transition. The blanking interval circuit provides outputs which control the latches and selects the latch output to be transferred to the multiplexer output such that the multiplexer output is prevented from transitioning during a blanking interval. An 'adaptive' blanking circuit is also described in which the blanking interval is terminated when the transition which triggered the start of the blanking interval propagates through an entire signal path, such that the blanking interval is automatically adjusted to be the same as the signal path delay.

Digital banking circuit

An inductor current emulation circuit for a switched-mode power supply (SMPS) which is arranged such that its inductor current (I) goes to zero at least once per switching cycle. The emulation circuit includes an RC integrator connected in parallel across the inductor, and a zero reset switch (ZRS) connected in parallel across the integrator's capacitor. A control circuit operates the ZRS such that it is opened when Iis non-zero, and is closed for a least a portion of the time during each switching cycle when Iis zero such that the capacitor is substantially discharged. In this way, the ZRS essentially recalibrates the emulation circuit when Iis zero. When so arranged, the voltage (V) across the capacitor emulates I. The invention may be implemented with either a discontinuous-inductor-current SMPS, or a continuous-bipolar-inductor-current SMPS.

Inductor current emulation circuit for switching power supply

A method and circuit enable a voltage regulator to employ the smallest possible output capacitor that allows the regulator's output voltage to be maintained within specified boundaries for large bidirectional step changes in load current. This is achieved with a technique referred to as &ldquo;optimal voltage positioning&rdquo;, which keeps the output voltage within the specified boundaries while employing an output capacitor which has a combination of the largest possible equivalent series resistance (ESR) and lowest possible capacitance that ensures that the peak voltage deviation for a step change in load current is no greater than the maximum allowed. The invention can be used with regulators subject to design requirements that specify a minimum time T,between load transients, and with those for which no T,is specified. When no T,is specified, optimal voltage positioning is achieved by compensating the regulator to ensure a response that is flat after the occurrence of the peak deviation, which enables the output voltage to remain within specified limits regardless of how quickly load transients occur. Another embodiment enables the power consumption of the device being powered by the regulator to be reduced under certain circumstances, while still employing the smallest possible output capacitor that allows the regulator's output voltage to be maintained within specified boundaries. The invention is applicable to both switching and linear voltage regulators.

Voltage regulator compensation circuit and method

A method and circuit enable a voltage regulator to employ the smallest possible output capacitor that allows the regulator's output voltage to be maintained within specified boundaries for large bidirectional step changes in load current. This is achieved by employing an output capacitor which has a combination of the largest possible equivalent series resistance (ESR) and lowest possible capacitance that ensures that the peak voltage deviation for a step change in load current is no greater than the maximum allowed, and by compensating the regulator to ensure a response that is flat after the occurrence of the peak deviation. The invention is applicable to both switching and linear voltage regulators.

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Carlsbad, CA, United States of America

Brian P Erisman