Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
149 words
In a digital to analog converter, an apparatus for generating a voltage control signal using either one of a voltage reference source and a current reference source, comprising: transistor means responsive to a supply voltage and said voltage control signal to produce a controlled current; operational amplifier means for generating said voltage control signal in response to said voltage reference source; and switch means for generating said voltage control signal in response to said current reference source, wherein when said switch means is in one state thereof, an output signal of said operational amplifier means is connected through said transistor means in a closed loop back to an input terminal of said operational amplifier means, and when said switch is in another state thereof said output signal of said operational amplifier means is connected directly in a closed loop back to an input terminal of said operational amplifier means.
Claim 2
Dependent Claim
149 words
In a digital to analog converter, an apparatus for generating a voltage control signal using either one of a voltage reference source and a current reference source, comprising: transistor means responsive to a supply voltage and said voltage control signal to produce a controlled current; operational amplifier means for generating said voltage control signal in response to said voltage reference source; and switch means for generating said voltage control signal in response to said current reference source, wherein when said switch means is in one state thereof, an output signal of said operational amplifier means is connected through said transistor means in a closed loop back to an input terminal of said operational amplifier means, and when said switch is in another state thereof said output signal of said operational amplifier means is connected directly in a closed loop back to an input terminal of said operational amplifier means.
Claim 3
Dependent Claim
15 words
The apparatus of claim 1 wherein said switch means operates as a single-throw, single-pole switch.
Claim 4
Dependent Claim
14 words
The apparatus of claim 2 wherein said switch means is a pass gate device.
Claim 5
Dependent Claim
16 words
The apparatus of claim 2 wherein said switch means is realized by a bonding wire option.
Claim 6
Dependent Claim
32 words
The apparatus of claim 1 wherein said operational amplifier means is an operational transconductance amplifier having a low current output capability as compared to said current reference source and said controlled current.
Claim 7
Dependent Claim
13 words
The apparatus of claim 5 wherein said transistor means is a P-channel MOSFET.
Claim 8
Dependent Claim
123 words
The apparatus of claim 6 further comprising a plurality of cells each connected to receive said voltage control signal, each cell comprising: a P-channel MOSFET responsive to said supply voltage and said voltage control signal to generate current substantial equal to said controlled current; and a pair of MOSFETs each connected to receive said current at a source at each of said MOSFETs, one of said MOSFETs operating to shunt said current to circuit ground in accordance with a logic signal applied to a gate of said one of said MOSFETs and another of said MOSFETs operating to channel said current to an output terminal in accordance with an opposite logic signal applied to a gate of said another of s id MOSFETs.
Claim 9
Dependent Claim
20 words
The apparatus of claim 6 further comprising a compensating capacitor connected to said output signal of said operational amplifier means.