摘要 |
A device includes a light emitter, a current sensing resistance, a current generator, and detection circuitry. The current generator is connected to the light emitter and to the current sensing resistance. During a normal operating mode of the device, the current generator regulates current flow through the light emitter. In a test mode, the current generator regulates current flow through the current sensing resistance. The detection circuitry, during the test mode, detects when current flow through the current sensing resistance is outside an expected range.
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