Frequency compensated current output circuit with increased gain
AssigneeTexas Instruments Incorporated
InventorFrank J. Sweeney
Life of this patent
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Abstract
A frequency compensated current output circuit with increased gain. The current output circuit is an improved current mirror where the gate of an output transistor (MP06) is coupled to an impedance (Ra) located in the conductive path of the mirror transistor (MP05), so that the current flowing out of the circuit is increased by an amount proportional to the resistive value of the impedance (Ra). The circuit includes a frequency compensation network (Rc, Cc) to offset the gain peaking effects which occur in the frequency response of the circuit due to the gain impedance. An output amplifier is described using the current output circuit. Other embodiments are described.
Claims8
A current mirror circuit, comprising:
- a circuit output terminal for outputting a current;
- a circuit input terminal for receiving an input voltage;
- a first transistor having first and second electrodes and a current path between said first and second electrodes, said current path of said first transistor coupled between said circuit output terminal and a first voltage source, and said first transistor having a control electrode;
- a second transistor having first and second electrodes and a current path between first and second electrodes, said current path of said second transistor coupled between said first voltage source and a reference node, and said second transistor having a control electrode coupled to said reference node;
- an impedance having a first terminal coupled to said reference node and having a second terminal coupled to the control electrode of said first transistor;
- a third transistor having first and second electrodes and a current path between first and second electrodes, said current path of said third transistor coupled between said second terminal of said impedance and a second voltage source, said third transistor having a control electrode coupled to said circuit input terminal, and said third transistor controlling the current flowing in said impedance responsive to a voltage input at said circuit input terminal;
- and
- frequency compensation circuitry coupled having a first terminal coupled to said reference node and a second terminal coupled to the control electrode of said third transistor.
Dependencies are inferred from the claim text.