Faraday Technology Corporation

Uei-Shan Uang

Mei-Show Chen

Kuen-Shan Chang

Yan-Hua Peng

Chia-Ming Hong

A bandgap reference circuit includes a reference current generator for respectively generating a first reference current on a first current path and a second reference current on a second current path, a current mirror for generating a third reference current on a third current path based on the first and second reference currents, an operation amplifier for rendering the first reference current substantially identical to the second reference current and a feedback circuit for rendering a node voltage on the first current path substantially identical to another node voltage on the third current path, so as to eliminate possible errors caused by a channel length modulation effect in the current mirror.

Bandgap reference circuit

A bandgap reference circuit comprises: a current generator for generating an output current, the current generator comprising a first reference unit and a plurality of second reference units arranged in parallel, where the current generator is capable of determining the magnitude of the output current according to the reference units; a first resistor, coupled between a first terminal of the first reference unit and a node, for transmitting a first current; a second resistor, coupled to the node and a first terminal of each second reference unit, for transmitting a second current; a third resistor, coupled between the node and an output terminal of the bandgap reference circuit, for transmitting a third current; and a current-to-voltage converter, coupled to the third resistor, for generating a bandgap voltage according to the output current and the third current.

Bandgap reference circuits

A low supply voltage band-gap reference circuit is provided, which includes a positive temperature coefficient current generation unit and a negative temperature coefficient current generation unit, and it is implemented by way of current summing. Through the current-mode temperature compensation technique, the present invention is able to reduce the voltage headroom and the number of operational amplifiers required by the conventional voltage-summing method, as well as the influence to the output voltage due to the offset voltage, thereby providing a stable and low voltage band-gap reference voltage level. In addition, by reducing the number of operational amplifiers and resistors of high resistance, the circuit area is reduced, and chip cost is saved.

Low supply voltage band-gap reference circuit and negative temperature coefficient current generation unit thereof and method for supplying band-gap reference current

A non-linearity compensation circuit and a bandgap reference circuit using the same for compensating non-linear effects of a reference voltage are provided. In the non-linearity compensation circuit, the reference voltage is transformed into a temperature independent current. A current mirror mirrors the temperature independent current for biasing a bipolar junction transistor (BJT). Further, two resistors are used for estimating a non-linear voltage, so as to compensate the reference voltage.

Non-linearity compensation circuit and bandgap reference circuit using the same

A voltage reference circuit including a positive temperature coefficient current generator, a negative temperature coefficient current generator, and a first resistor is provided. In the positive temperature coefficient current generator, two transistors are operated in the weak inversion region, and a second resistor is connected in series between the gates of the two transistors. The second resistor employs the characteristic that a transistor operated in weak inversion region acts like a bipolar junction transistor to generate a positive temperature coefficient current. The negative temperature coefficient current generator generates a negative temperature coefficient current in response to a negative temperature coefficient voltage drop on a third resistor. The positive temperature coefficient current and the negative temperature coefficient current flow through the first resistor together, thus producing a stable reference voltage.

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Taichung County, Taiwan

Uei-Shan Uang