LDS8846

© 2009 IXYS Corp.

7

Doc. No. 8846DS, Rev. N1.6

Characteristics subject to change without notice

Unused LED Channels

For applications with only two or three LEDs, unused

LED can be disabled via the appropriate CTRL pins

logic states. For applications requiring 1 LED only,

However,

we

recommend

use

of

all channels

connecting

them

in

parallel

with

accordingly

decreased current per channel. If one LED is used

only, current per channel should be decreased four

times, or this device may drive one LED with

maximum current up to 120 mA with all channels

connected in prallel and 30 mA current per chennel.

Figure 3. Application circuit with three LEDs

Figure 4. Application circuit with two LEDs

Figure 5. Application circuit with two LEDs

Figure 5. Application circuit with one LED

Protection Mode

shorted to ground either before or after device start.

This is to prevent the device from overload in case of

short circuit at the output. Device resumes normal

operation after short removed.

If the die temperature exceeds +150°C, the driver will

enter thermal protection shutdown mode. When the

device temperature drops by about 20°C, the device

resumes normal operation.

If the input voltage is below under-voltage protection

threshold, device turns into shutdown mode with high

LED Selection

4.5 V may be used. The device exhibits the highest

voltage source is a Li-ion battery, we recommend

minimum expected battery discharging voltage to

extend the battery life and achieve highest efficiency.

If the minimum battery discharging voltage is limited

2.95 V

External Components

The driver requires only one external component –

connected to the voltage source (battery) through

long traces, or voltage source has high electrical

noise due bad performance of other components

connected to this source, we recommend 1uF

decoupling capacitors

located as close to he device as possible.

that

allows

use

of

very

small

surface

mount

component.