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).
Claims10
A band gap reference circuit, comprising:
- a current source providing a current to a charging node operating at a potential that determines an output voltage of the band gap reference circuit;
- and
- a differential input stage coupled for sensing the output voltage to produce an error signal for controlling a magnitude of the current.
A band gap reference circuit comprises:
- a current source providing a current to a charging node operating at a potential that tracks an output voltage of the band gap reference circuit, the current source having a first current mirror circuit that receives a first component of an error signal for charging the node with the current;
- a first feedback stage having a first transistor with a control terminal coupled to receive the first component of the error signal and having a conduction terminal coupled to a second node;
- a second transistor of the first feedback stage having a control terminal coupled to receive a second component of the error signal and having a conduction terminal coupled to the second node;
- a second current mirror circuit of the current source that receives the second component of the error signal for discharging the node with the current;
- a differential input stage having a first transistor having a control terminal coupled to receive a first feedback signal representative of the output voltage and a first conductor coupled to provide the first component of the error signal;
- the differential input stage coupled for sensing the output voltage to produce the error signal for controlling a magnitude of the current;
- a second transistor of the differential input stage having a control terminal coupled to receive a second feedback signal representative of the output voltage and a first conductor coupled to provide the second component of the error signal.
A method of generating a reference signal, comprising:
- sensing a change in the reference signal to adjust a magnitude of a current;
- supplying the current to a node to modify a node potential;
- and
- level shifting the node potential to correct the reference signal.
Dependencies are inferred from the claim text.