Negative reference voltage generating circuit and system thereof
a reference voltage and generating circuit technology, applied in the field of negative reference voltage generating circuits, can solve the problems of additional errors, differential amplifier offsets are added, and further errors, and achieve the effect of simple circuit structure and high accuracy
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embodiment 2
[0077]FIG. 2A is a circuit diagram showing a structure of the BGR type negative reference voltage generating circuit of Embodiment 2. The BGR type negative reference voltage generating circuit of Embodiment 2 is different from the BGR type negative reference voltage generating circuit of Embodiment 1 in the following aspects.
(1) a NPN type transistor Qc with diode connection is provided in place of the diode Dc.
(2) m NPN type transistors Q1-Qm respectively with diode connection are provided in place of the diodes D1-Dm.
[0078]FIG. 2B is a vertical cross-sectional view showing a triple well structure of the NPN type transistors Q1-Qm and Qc of the BGR type negative reference voltage generating circuit of FIG. 2A. Each of the NPN type transistors Q1-Qm and Qc has the structure as shown in FIG. 2B, for example. In FIG. 2B, an N type dopant, such as phosphorus, is implanted into the P type semiconductor substrate 10 to form the N well 11, and a P type dopant, such as boron, is implanted ...
embodiment 3
[0081]FIG. 3A is a circuit diagram showing a structural example of the differential amplifier 1, operated by a negative voltage, of Embodiment 3. In FIG. 3A, the differential amplifier 1 is an operational amplifier and includes MOS transistors M1-M8, a bias resistor Rbias, a phase compensation capacitor Cc, input terminals T1 and T2, and an output terminal T3. The positive power voltage terminal of the differential amplifier 1 is set to the ground voltage Vss (may also be the positive power voltage Vdd as shown in FIG. 1A or FIG. 2A). The differential amplifier 1 differentially amplifies a differential input voltage inputted to the non-inverting input terminal T1 and the inverting input terminal T2, and outputs the same from the output terminal T3. Here, Vss is the ground voltage and Vnn is a predetermined negative voltage.
[0082]The differential amplifier 1 used in Embodiment 1 and Embodiment 2 needs to be operated by the negative power voltage Vnn. The initial negative power voltag...
embodiment 4
[0084]FIG. 4 is a block diagram showing a structural example of a negative reference voltage generating system of Embodiment 4. The BGR type negative reference voltage generating circuit of Embodiment 1 or Embodiment 2 requires the negative power voltage Vim, which needs to be generated from the positive power voltage Vdd. In FIG. 4, the negative reference voltage generating system of Embodiment 4 includes a negative voltage generating circuit 71 and a BGR type negative reference voltage generating circuit 72 as described in Embodiment 1 or Embodiment 2, for example. Here, the negative voltage generating circuit 71 does not include an output voltage controller and can generate a negative voltage around −Vdd by a one-stage charge pump driven by the positive power voltage Vdd or a switched capacitor converter driven by the positive power voltage Vdd.
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