Canon 580EX - Speedlite II - Hot-shoe clip-on..., Service Manual, Page: 23 / 97

Technical Information
. ICS & PDS
1) IC
Ckt Brd Symbol Name Function
A IC107S MPU Overall Control
A IC106S Comparator IC Controls signal comparisons
A IC101S EEPROM Stores electrical adjustment settings.
A IC102S Metering IC Flash output control
A IC19 OR Gate Remote control pulse shaping control
A IC15 Step-up Voltage regulator Generates a regulated 5.5V
A IC16 Voltage regulator IC Generates Digital VCC (4.8V)
A IC17 Voltage regulator IC Generates Analog E1 (4.8V)
A IC4 Voltage-detector IC Starts MPU according to VCC detection result.
A IC18 Motor driver Controls the zoom motor.
C IC108S Operation amp Stabilizes the Area AF-assist light intensity.
B IC304 NOR Gate Gate control of converter FET
I IC20 Analog switch Switches optical sensor
2) PDs
Brd Symbol Function
PD3 Pilot Lamp (Charge completion)
PD5 Flash Check Lamp
PD1 AF assist beam LED (Horizontal AF)
PD9 AF assist beam LED (Vertical AF)
PD2 AF assist beam LED (Area AF)
PD8 Remote Control Receptor Sensor
PD10 Flash control optical sensor
PD11 External flash metering sensor