Browse Prior Art Database

Remote Soft/Hard Power Up/Down Control

IP.com Disclosure Number: IPCOM000030626D
Original Publication Date: 2004-Aug-20
Included in the Prior Art Database: 2004-Aug-20
Document File: 2 page(s) / 85K

Publishing Venue

IBM

Abstract

Usually, the power up/down control line acts as a request to the processor for a "soft" orderly shutdown. This invention provides 2 ways to shut DC power down to the card even when the processor/code is hung and cannot respond to a request for a soft shutdown.

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Remote Soft/Hard Power Up/Down Control

     This design provides a design that supports remote soft power up/down with two added features.

The first is that there is a hard shutdown override that stops waiting for a soft shutdown complete response from the processor after a fixed (or programmable) period of time. Figure 1 shows one implementation of the hard shutdown override circuit. This circuit divides the 14.318MHz clock down to various lower frequencies. One can select the timing of shutdown by connecting the hard shutdown signal (U14) to the frequency taps on the timers (U44, U45, U46). In this particular configuration, the hard shutdown would activate in about 1.25 minutes.

     The second feature is the capability of forcing an immediate hard shutdown by "double clicking" the power up/down control line (by a switch for instance). Figure 2 shows the immediate hard shutdown circuit. The circuit detects the pressing of the switch (U35). Each time the switch is pressed, it changes the state of the state machine. After the switch is pressed for the second time, the PS_ON* is de-activated and forces an immediate power off.

Figure 1: Delayed hard shutdown circuit

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Figure 2: Immediate hard shutdown circuit

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