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发表于 2009-8-29 23:05:13
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Patent number: 6489835
Low Voltage Bandgap Reference Circuit
Patent number: 6489835
Filing date: Aug 28, 2001
Issue date: Dec 3, 2002
Inventors: Quan Yu, Edwin Chan
Assignee: Lattice Semiconductor Corporation
Banba et al, in "A CMOS Bandgap Reference Circuit with Sub-1-V Opeation", discloses a bandgap reference circuit that can operate at supply voltage down to about 1V. This configuration needs two additional resistors, RA and RB, to generate CTAT currents. However, these two resistors will result in more than one opeating point, especially when the drain voltages of PMOS transistors, drops below ΔVbe(i.e., when the two bipolar devices are turns off). Existence of more than one opeating point makes the start-up circuit very complex, or requires an additional circuit to gurantee achievement of a proper operating point. Without such a circuit, the risk of having an undesired operating point is high.
This configuration differs from Banba's circuit in several ways.
1. Only one resistor, RC, is added to provide an CTAT current, rather than need two such resistors.
2. Only one non-zero initial current, and this system will move to this point after power-up. |
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