Laser driving open circuit detection circuit

Abstract

The invention discloses a laser driving open circuit detection circuit, which is provided with a driving circuit, and comprises a laser driving circuit, a laser and a first monitoring circuit, the output end of the laser driving circuit is connected to the anode end of the laser, and the first monitoring circuit is connected to the output end of the laser driving circuit to obtain a monitoring voltage VOUT1; the reference voltage generating circuit comprises a driving mirror image circuit, a laser equivalent circuit and a second monitoring circuit, and the second monitoring circuit is connected to the output end of the driving mirror image circuit to obtain reference voltage VOUTREF; and the monitoring voltage VOUT1 and the reference voltage VOUTREF are connected with the input end of the comparator, and whether the connection between the driving circuit and the laser is normal or not is judged according to the output result of the comparator. The detection circuit does not influence the normal working state of the driving circuit, the judgment process is real-time and automatic, human intervention is not needed, power-off operation or external detection tools are not needed, and the detection circuit is simple in structure, easy to implement and low in power consumption.

Description

technical field [0001] The invention relates to a circuit detection circuit, in particular to a laser drive open circuit detection circuit. Background technique [0002] In the production process of the laser driver module (especially during the packaging and bonding process of the laser and the driver chip) or in the use stage of the laser driver module (due to external force factors or other factors), there will be disconnection between the driver chip and the laser. Phenomenon, so that the driving current cannot flow into the laser normally, and the laser cannot emit light normally. Powering off the driver module and using a third-party testing tool can detect the open circuit between the driver chip and the laser, but this method is obviously time-consuming and resource-intensive. In order to reduce the detection time and cost of open-circuit bonding, it is necessary to design a detection circuit inside the driver chip that can automatically detect whether the bonding w...

AI Technical Summary

Problems solved by technology

[0004] 1. Connecting a resistor in series with the output end of the laser will reduce the modulation current amplitude of the laser

[0005] 2. Connecting a resistor in series with the output end of the laser will consume a certain voltage margin, reduce the maximum value of the bias current that the laser can work, and generate unnecessary energy consumption at the same time

[0006] 3. Connecting a resistor in series with the output end of the laser will affect the performance of the drive current (rise and fall time, amplitude, etc.)

[0007] 4. The presence of parasitic capacitance at the input of the amplifier DIFF_AMP will also affect the bandwidth of the drive circuit, which in turn will affect the rise and fall time of the drive current, etc.

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