Lattice Semiconductor Corporation

Frederic N F Deboes

Hans W Klein

Ludmil Nikolov

Douglas C Morse

Geoffrey R Richard

Power-sequencing controllers are connected to allow more complex power sequencing and/or larger numbers of voltage supplies to be monitored than with a single controller. Power-on-reset (POR) output signals from the 'slave' controllers are connected by a wired-OR, and the composite output is used as a reset signal or indicator signal by the 'master' controller. An output from the master controller coupled to the composite input signal is connected with the {overscore (POR)} output of the master controller by a wired-OR, and this composite signal is coupled to the reset terminals of the slave controllers. Connecting controllers in a master/slave configuration allows prevents any of the slave devices from starting until all the devices have been released, resulting in synchronous processing of subsequent signals and events.

Expansion method for complex power-sequencing applications

Power supply sequencing systems and methods are disclosed. In one embodiment, a programmable charge pump supplies a programmable current source, which drives an external NFET that controls whether power is supplied to a device or a portion of circuitry. The maximum voltage and the turn-on ramp rate supplied to the NFET are programmable and, therefore, the NFET can be operated safely within its rated limits without requiring external protection devices. If a high-voltage output terminal is not required to drive an external NFET, the output terminal, in accordance with another embodiment, may be configured to function as an open drain logic output terminal.

Growing community of inventors

Austin, TX, United States of America

Frederic N F Deboes