Low power wake up circuitry, with internal power down of the wake up circuitry itself

• US 5,991,887 A
• Filed: 08/19/1998
• Issued: 11/23/1999
• Est. Priority Date: 02/28/1996
• Status: Expired due to Fees

• Current Assignee: Dallas Semiconductor Corporation (Analog Devices, Inc.)
• Original Assignee: Dallas Semiconductor Corporation (Analog Devices, Inc.)
• Inventors: Ezell, Richard William
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US09/136,787
• Time in Patent Office: 461 Days
• Field of Search: 395/750.08, 395/750.07, 395/750.01, 327/143, 327/198, 713/340, 713/330, 713/324, 713/300, 713/1, 714/22, 326/46
• US Class Current: 713/340
• CPC Class Codes: G06F 1/24 Resetting means
• CPC Class Codes: G06F 1/305 in the event of power-supply fluctuations
• CPC Class Codes: G06F 11/0754 by exceeding limits

Abstract

An initializer that responds to change in a power supply potential level, for generating an initialize signal to initialize a circuit to a select state, the initializer includes a power-on reset circuit that switches between an active and a powered-down state, and is for generating the initialize signal. The initializer also includes a wake-up circuit that monitors the power supply potential level and switches the power-on reset circuit from the powered-down state to the active state when selected change in the power supply potential level occurs.

Claims

1. A power reset circuit, operable in response to changes, and the level of a power supply level, for generating a signal to switch the state of a component, wherein said component has at least two states, the first of which is a low-power standby state and at least one second active state, and wherein the switching occurs from the low-power standby state to at least one of the active state, said power reset circuitry comprising:

a means to couple both said power reset circuitry and said component to a power supply potential;

a detector coupled to said means to couple for detecting in the power supply potential level;

a signal generator coupled to said detector, said signal generator for generating the signal to switch the state of the component from the low-power standby state to the active state when said detector detects at least a selected amount of change in the power supply potential level; and

a switching means to power-down at least a portion of said power reset circuitry upon the detection of the power supply voltage reaching a predetermined level and wherein said power reset circuit itself also has a low-power standby state.

2. A circuit as recited in claim 1, wherein:

said detector includes means for generating a reference potential; and

said signal generator generates the signal when the power supply potential level is at least a selected amount less than said reference potential.

3. A circuit as recited in claim 2, wherein:

said reference potential generating means includes at least one capacitor.

4. A circuit as recited in claim 3, wherein:

said at least one capacitor is charged by the power supply.

5. A circuit as recited in claim 1, wherein:

said signal generator is a one shot pulse generator.

6. A circuit as in claim 1 wherein the predetermined level of the power supply voltage, at which at least a portion of said power reset circuit is powered down is a minimum operating voltage of the component.