Margining pin interface circuit for clock adjustment of digital to analog converter
AssigneeIntersil Americas Inc.
InventorHarold Allen Wittlinger
Life of this patent
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Abstract
A voltage margin setting interface circuit has a single input pin, and is configured to program the slew rate and polarity direction of variation of the operation of a digital-to-analog converter, such as may be used to set a reference voltage level, for application to an error amplifier of a voltage regulator circuit of the power supply of a personal computer. A DAC clocking control circuit is coupled to an output port, and to respective DAC increment and decrement ports, and is operative to control the magnitude of output current, and to assert an output signal at one of the increment and decrement ports, in accordance with a prescribed relationship between the voltage and upper and lower ranges of the input voltage relative to its middle value.
Claims20
A circuit for controlling the operation of a digital-to-analog converter (DAC) comprising:
- an input port to which an input voltage is coupled;
- an output port from which an output current that is adapted to control the clock frequency of the:DAC is provided;
- a DAC clock adjustment circuit, coupled to said output port, and being coupled between said input port and respective increment and decrement ports, that are adapted to be coupled to associated increment and decrement clock control inputs of said DAC, said DAC clock adjustment circuit being operative to control said output current, and to assert an output signal at one of said increment and decrement ports, in accordance with a prescribed relationship between the value of said input voltage and a range of variation thereof.
A method of controlling the operation of a digital-to-analog converter (DAC) comprising the steps of:
- (a) providing an input port;
- (b) providing an output port from which an output current that controls the clock frequency of the DAC is derived;
- (c) providing respective DAC increment and DAC decrement ports that are adapted to be coupled to associated increment and decrement control inputs of said DAC;
- and
- (d) controlling the magnitude of said output current and selectively asserting an output signal at one of said DAC increment and decrement DAC ports, in accordance with a prescribed relationship between the value of said input voltage and a range of variation thereof.
A circuit for determining the relationship between and input voltage and a reference voltage comprising:
- an input port to which an input voltage is coupled;
- first, second and third output ports;
- a comparator circuit, coupled between said input port and said first, second and third output ports, and being operative to assert an output signal at said first output port in response to said input voltage being higher than said reference voltage, and being operative to assert an output signal at said second output port in response to said input voltage being less than said reference voltage, and to supply to said third output port an output current representative of the difference between said input voltage and said reference voltage.
Dependencies are inferred from the claim text.