Low power implementation to allow for high potential rails to come up in any order
AssigneeATI Technologies ULC
InventorsJason J. Mangattur, Richard W. Fung, Marcus Ng
Life of this patent
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Abstract
A low power biasing circuit for powering up split-rail electronic circuits includes an intermediate voltage generator at each pad which is supplied by a temporary supply voltage to generate a temporary intermediate voltage only when a power signal indicates that all external voltage rails are not safe, thereby reducing power consumption.
Claims20
An apparatus for powering an electronic circuit, comprising:
- a first temporary voltage generator for generating a temporary supply voltage when a power safe signal indicates that one or more external power supply rails are not powered up;
- and
- a second temporary voltage generator for generating an intermediate output voltage by:
- selecting an intermediate voltage generated by an intermediate voltage generator that is powered by the temporary supply voltage only when the power safe signal indicates that one or more external power supply rails are not powered up, and
- selecting an external intermediate voltage when the power safe signal indicates that the one or more external power supply rails are powered up.
A method for biasing a split power supply based circuit during power up comprising:
- generating a temporary supply voltage which is high when a first power signal indicates that one or more external power supply rails are not powered up, and which is low when the first power signal indicates all external power supply rails are powered up;
- generating an intermediate output voltage by powering an intermediate voltage generator with the temporary supply voltage to generate the intermediate output voltage when the first power signal indicates that one or more external power supply rails are not powered up, and by providing an external intermediate voltage as the intermediate output voltage and powering down the intermediate voltage generator when the first power signal indicates that all of the one or more external power supply rails are powered up.
The method of claim where the generating the intermediate output voltage comprises powering a resistor divider network with the temporary supply voltage to generate a first intermediate voltage at an output node of the resistor divider network only when the first power signal indicates that one or more external power supply rails are not powered up.
A power up biasing circuit for a split power supply integrated circuit comprising:
- a first voltage generator for generating a temporary first reference voltage that is shared by a plurality of circuit areas when a power safe signal indicates that one or more external power rails are not powered up;
- and
- a second voltage generator in each of the plurality of circuit areas for generating a second reference voltage from the temporary first reference voltage when the power safe signal indicates that one or more external power rails are not powered up, and for generating the second reference voltage from an external reference voltage when the power safe signal indicates that all of the one or more external power rails are powered up.
Dependencies are inferred from the claim text.