Triple 60mA Linear LED Controller
Preliminary Information - Jan 21, 2015
E522.84/85/86/87
5 Functional Description
5.1 Overview
E522.84/85/86/87 family devices provide triple linear current controler for LED driving, which can optionally be operated in
parallel for higher current requirements. These family members support common current configuration for all channels with
a single resistor plus digital PWM dimming via fast ENA input.
Various diagnostic features are provided to meet automotive requirements, together with a communication interface named
“RUN” to link ICs. If linked in this way, the ICs can be operated as a combined cluster of drivers, turning ‘on’ and ‘off’ in parallel
(e.g. turning all drivers ‘off’ in case of hardware failures).
“Single Lamp Mode” operation is implemented to support legal requirements, e.g. regarding automotive lighting.
Typical exemplary application topologies are presented in „5.7 Exemplary Application Topologies“.
More information on the LEDx drivers can be found in „5.2 LED Driver“.
For more details on the configuration via IR interface see „5.3 IR Driver“.
A detailed overview of functional states is given in „5.4 State Diagram“.
Diagnostic features are described in „5.5 RUN Interface and Diagnostics“.
For more advanced features, see family members E522.80/81/82/83, which provide e.g.:
- more current per channel
- active failure feedback operation
- additional powermanagement /-distribution options
- independent current configuration per channel
- independent digital dimming for each channel
5.2 LED Driver
Highside drivers for LEDx provide the current configured by IR pin, reproducing the IIR with a typical amplification factor of 385:1.
The LEDx outputs are monitored for short-circuit condition to GND (undervoltage) and open condition (ILEDx smaller than rela-
tive threshold ILEDx,OPEN). IR configuration is monitored separately, see diagnostic chapter 5.5 for details.
For parallel operation, the total output amplification factor is 1155:1. Monitoring functions (e.g. ‘open’ detection) remain active
per channel, thus a loss of a single LEDx output connection will be detected.
5.3 IR Driver
ENA
ENABLE /
Dimming
+
1.2V
-
VREF,NOM
VREF,HV
VS Overvoltage
LEDx
Current
Reference
250kΩ
+
+
+
-
250kΩ
IR
Internal
Temperature
Derating
Figure 1. IR Reference Generation
This document contains information on a pre-production product. Elmos Semiconductor AG reserves the right to change specifications and information herein without notice.
Elmos Semiconductor AG
Data Sheet
QM-No.: 25DS0137E.00
9/20
ELMOS [ ELMOS SEMICONDUCTOR AG ]
