An optical receiver can implement a transimpedance amplifier (TIA) to process received light using a closed loop optical pre-amplification. The optical receiver can use an average input value of the TIA to control an semiconductor optical amplifier (SOA) or pre-amplification as received average signal varies. The optical receiver can include a gain controller for the TIA that can measure the TIA swing to adjust the gain of the SOA to pre-amplify received light in a closed loop control configuration.

An amplifier circuit includes a constant current circuit for outputting a constant current signal at its output terminal, an operational amplifier for outputting an amplified control signal based on the first voltage signal, and an amplified voltage output circuit for outputting a second voltage signal based on both the constant current signal and the amplified control signal. The constant current circuit has a light-emitting device having one end supplied with the constant voltage signal and another end supplied with ground potential, a light responsive electricity generating device for outputting a drive signal in response to light emitted by the light-emitting device, a first transistor generating the constant current signal based on the amplified voltage signal applied thereto and to output the constant current signal; and a current control circuit for detecting the value of the constant current signal and controlling the supply of the drive signal based on the detection.

A power supply apparatus to supply power to an image forming device, the power supply apparatus includes an amplifier to amplify an input AC power by a general amplification or a double amplification, a converter to receipt the input AC power amplified by the general amplification or the double amplification and output a DC power with a determined size. A controller control applying the general amplification or the double amplification to the converter, in response to an operating mode of the image forming device.

An electronic circuit includes an isolation amplifier, having a first input terminal receiving an AC-signal and including a linear opto-isolator. The opto-isolator has a first output terminal that provides a unipolar signal having an AC-component proportional to the input signal. The circuit includes a transimpedance receiver with first and second operational amplifiers. The first amplifier has a second output terminal and first and second differential input terminals, with the first differential input terminal receiving and amplifying the unipolar output signal from the first output terminal providing an output signal from the circuit at the second output terminal. The second amplifier is configured as an integrator, having a third output terminal coupled to the second differential input terminal and having third and fourth differential input terminals, with the third differential input terminal receiving the output signal from the second output terminal and the fourth differential input terminal connected to ground.

An isolation circuit and a method for providing isolation between two dies are provided. The isolation circuit includes: an isolation module, configured to generate an isolation signal based on an input signal from a first die and to provide isolation between the first die and a second die, where the isolation signal is smaller than the input signal in amplitude, and the first die is coupled with the second die; a latch module, configured to latch the isolation signal at a certain level and output a latched signal; an amplifier module, configured to amplify the latched signal. In the isolation circuit, a modulation module and a demodulation module can be saved.

An isolation amplifier of an embodiment includes: a primary circuit including an encoder configured to encode an input signal and output the encoded input signal and an anomaly detection circuit configured to detect anomaly having occurred to the input signal and generate a detection signal; an isolation unit configured to insulate the primary circuit from a secondary circuit; an output circuit configured to generate an output signal corresponding to the input signal; and an anomaly-input sensing-output circuit configured to generate an output signal from the secondary circuit by changing the output signal from the output circuit based on the detection signal.

A Regulated Cascode (RGC)-type burst mode optic pre-amplifier having an extended linear input range. The burst mode optic pre-amplifier comprises an RGC-type Trans Impedance Amplifier (TIA), wherein a current path is added in the circuit of the RGC-type TIA to control a linearity state of the RGC-type TIA, and a main voltage gain is controlled in other circuit blocks after the RGC-type TIA.

Disclosed are a constant current generation circuit for optocoupler isolation amplifier and a current precision adjustment method. The constant current generation circuit includes a start circuit, a current generation circuit and a precision adjustment and output circuit integrated into a same substrate. The start circuit can generate and output a first start current and a second start current. The current generation circuit includes a negative temperature change rate current generation circuit connected to a first start current output and a positive temperature change rate current generation circuit connected to a second start current output. The precision adjustment and output circuit outputs constant current meeting application requirements of optocoupler isolation amplifier by adjusting proportional precision of two currents output from a current generation circuit. The disclosure forms a constant current output circuit which is independent of temperature changes, power supply voltage changes and changes in technological parameters of current sheets.

An optical receiver can implement a transimpedance amplifier (TIA) to process received light using a closed loop optical pre-amplification. The optical receiver can use an average input value of the TIA to control an semiconductor optical amplifier (SOA) or pre-amplification as received average signal varies. The optical receiver can include a gain controller for the TIA that can measure the TIA swing to adjust the gain of the SOA to pre-amplify received light in a closed loop control configuration.

A power supply apparatus to supply power to an image forming device, the power supply apparatus includes an amplifier to amplify an input AC power by a general amplification or a double amplification, a converter to receipt the input AC power amplified by the general amplification or the double amplification and output a DC power with a determined size. A controller control applying the general amplification or the double amplification to the converter, in response to an operating mode of the image forming device.