Reduced noise band gap reference with current feedback and method of using
AssigneeSemiconductor Components Industries, LLC
InventorPetr Kadanka
Life of this patent
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Abstract
A band gap reference (32) provides low noise operation utilizing capacitor (98) to produce a low pass filter operating with high impedance node (104). Increased speed is realized using feedback signals at nodes (102) and (100) to control differential transistor pair (36, 42). A first current feedback stage using transistors (44, 50, 52 and 54) and a second current feedback stage using transistors (60, 62, 68, 70) is used to control current mirror stages which set the charge and discharge current at node (104). A first current mirror stage using transistors (64,76) comprise the current sink used to discharge capacitor (98) at node (104) and a second current mirror stage using transistors (58,74) comprise the current source used to charge capacitor (98) at node (104).
Claims19
A band gap reference circuit, comprising:
- a differential input stage coupled to receive first and second feedback signals and coupled to provide a differential error signal indicative of a difference between the first and second feedback signals;
- and
- a current feedback stage coupled to receive the error signal and coupled to provide first and second charge signals at a first node in response to the error signal.
A reference circuit providing a charging signal to an external filter element, the reference circuit comprising:
- a differential feedback stage coupled to receive a differential feedback signal and coupled to provide a differential control signal;
- and
- a current mirror stage coupled to receive the differential control signal and coupled to provide a charging signal at a charging node.
A method of operating a reference circuit, comprising:
- creating a reference signal derived from a supply potential;
- providing a feedback signal in response to the reference signal to produce a difference signal;
- and
- controlling a conductivity state of a current mirror in response to the difference signal to produce an output signal at a first node.
A method of operating a band gap reference circuit, comprising:
- establishing a reference signal in a first mode;
- detecting a change in the reference signal;
- creating a charge signal at a first node in response to a first change in the reference signal;
- and
- creating a discharge signal at the first node in response to a second change in the reference signal.
Dependencies are inferred from the claim text.