Patent ID: 11871492
Assignee: ROHM CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 15:
16. A light emitting element drive device comprising:
a driving circuit configured to supply a variable drive current to a light emitting unit including one or more light emitting elements, so that the light emitting unit is configured to emit light;
a drive reference voltage generation circuit configured to generate a drive reference voltage defining an upper limit value of the drive current, and supply the drive reference voltage to the driving circuit; and
a specific external terminal,
wherein:
the drive reference voltage generation circuit is operable selectively in a first mode to generate the drive reference voltage regardless of the state of the specific external terminal, or a second mode to generate the drive reference voltage in accordance with a second mode current through the specific external terminal,
the drive reference voltage generation circuit includes a current generation circuit configured to generate a predetermined current, and an internal resistor,
in the first mode the drive reference voltage generation circuit supplies the predetermined current to the internal resistor, so as to supply a voltage generated by the internal resistor as the drive reference voltage to the driving circuit, and
in the second mode the drive reference voltage generation circuit supplies the predetermined current as the second mode current to the specific external terminal, so as to supply a voltage generated at the specific external terminal as the drive reference voltage to the driving circuit.