Analog multiplying type of digital/analog converter circuit
AssigneeUnited Microelectronics Corp.
InventorChi-Mao Huang
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Abstract
An improved digital/analog converter circuit of the analog multiplying type for providing an adjustment for a DC voltage offset. The digital/analog converter circuit generally comprises a code converter, an analog multiplying current source and a bridge output circuit. The code converter converts the values of the tone data into 2's complement numbers. The numbers are then sent into an analog multiplying current source where positive and negative signals are produced to control the current path of a bridge-type output.
Claims8
A digital/analog converter circuit of the analog multiplying type for providing an adjustment for a DC voltage offset, said circuit comprising:
- a code converter for obtaining the magnitude and positive/negative sign of a tone data by a decoding method of 2's complement,
- an analog multiplying current source wherein an envelope signal is used to determine the DAC bias current,
- a tone signal is used to control an output current the magnitude of which is proportional to the product of the envelope signal and the tone signal, and
- a bridge output circuit which determines a current path depending on the positive or negative sign of the tone signal for driving a speaker output with no direct current component, said bridge output circuit not having a capacitively coupled component.
A digital/analog converter circuit of the analog multiplying type for providing an adjustment for a DC voltage offset, said circuit comprising a code converter utilizing a 2's complement code converting technique to obtain the magnitude and the positive/negative sign of a tone data, said code converter being connected to an analog multiplying current source and a bridge-type output circuit not having a capacitively coupled component.
Dependencies are inferred from the claim text.