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US 6,191,644 B1Granted
Startup circuit for bandgap reference circuit
AssigneeTexas Instruments Incorporated
InventorsBangalore Kodandaram Srinath, Scott E. Smith
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AssigneeTexas Instruments Incorporated
InventorsBangalore Kodandaram Srinath, Scott E. Smith
Estimating the term…
A bandgap reference circuit (10) with improved startup circuitry is disclosed. The bandgap reference circuit (10) includes a startup node (NBIAS) that is connected to the gates of n-channel MOS transistors (38n, 39n) in first and second conduction legs of a current mirror. A series of inverters (51, 53, 55) turn on a transistor (50) that is connected between a precharge node (TO) and the startup node (NBIAS) in response to a signal (RID) indicating recent power-up of a power supply voltage (Vdd). A capacitor (60) is also provided, and which is discharged upon power-down. The capacitor (60) is connected to the gate of a p-channel transistor (70) that has its source/drain path connected between the precharge node (TO) and the startup node (NBIAS), and that is turned on upon power-up, even if the power-up signal (RID) is not generated, thus ensuring initiation of the bandgap reference circuit (10).
A voltage reference circuit, comprising:
A method of initiating operation of a voltage reference circuit, the voltage reference circuit including a current mirror comprising a first conduction leg connected between a power supply voltage and a reference voltage, the first conduction leg having a first transistor with a control electrode connected to a startup node, and an output leg, coupled to the first conduction leg, and having an output node at which an output reference voltage is generated, the method comprising the steps of:
Dependencies are inferred from the claim text.