Micrel, Incorporated

Andrew Cowell

David W Ritter

Raymond David Zinn

John McGinty

An LDO regulator includes two linear regulator circuits and an internal priority logic scheme that favors generating a regulated output voltage using a regulated supply voltage over an unregulated supply voltage. The unregulated supply voltage is applied to a first input terminal from a raw voltage source. The regulated supply voltage is applied to a second input terminal from, for example, a switching (e.g., BUCK) regulator. Two output devices are respectively connected between the first and second input terminals and the LDO output terminal. The first regulator circuit causes the first output device to supply the desired regulated output voltage while the switching regulator ramps up. Once the regulated supply voltage is high enough to allow regulation, the internal priority logic scheme disables the first regulator circuit, whereby the desired regulated output voltage is generated solely by the second regulator circuit through the second output device.

Dual input prioritized LDO regulator

A non-synchronous boost converter includes a switched Schottky diode to rectify the switched output voltage of the boost converter where the switched Schottky diode has forward conduction blocking capability. The switched Schottky diode has an anode terminal coupled to receive the switched output voltage, a cathode terminal providing the output DC voltage, and a gate terminal coupled to receive a control signal. The control signal has a first state for turning the switched Schottky diode on where the switched Schottky diode conducts current when forward biased and a second state for turning the switched Schottky diode off where forward conduction of the switched Schottky diode is blocked even when the diode is forward biased. The switched Schottky diode can be a JFET controlled or an LDMOS gate controlled Schottky diode. Furthermore, the switched Schottky diode can be formed on-chip or off-chip of the controller circuit of the boost converter.

Non-synchronous boost converter including switched schottky diode for true disconnect

The present invention provides an apparatus and method for optimizing the efficiency of a switching converter for converting a first voltage to a second voltage. The apparatus includes a regulator, a DC-to-DC converter and a controller. The controller couples with both the regulator and DC-to-DC converter, and the controller is configured to activate and deactivate the regulator and the DC-to-DC converter depending on an output demand. In one embodiment, the controller is configured to activate the regulator and deactivate the DC-to-DC converter when the output demand transitions from a first demand level to a second demand level. The controller is further configured to activate the DC-to-DC converter and to deactivate the regulator when the output demand transitions from the second demand level to the first demand level. The apparatus is configured to monitor demand, and to activate the DC-to-DC converter when demand is in a first state or activate the regulator when demand is in a second state.

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Greytown, New Zealand

Andrew Cowell