AP8800EV1

Issue 3 – August 2009

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© Diodes Incorporated 2009

5

Figure 3: Component layout and circuit board view

AP8800EV1 Connection Point Definition

Name

Description

VIN

Positive supply voltage.

GND

Supply Ground (0V).

CTRL

Internal voltage ref. pin (1.25V). This pin can be used to achieve dimming and

soft-start, and for switching the output current off.

•

Leave floating for normal operation.

•

See 'Circuit Features' section to achieve dimming, soft-start and for

switching the output current off.

LED A

LED A

connects to the external LED anode

LED K

LED K

connects to the external LED cathode

AP8800EV1 Basic operation at full voltage

1.

Connect external LEDs across test pins ‘LED A’ (anode) and ‘LED K’ (cathode). The number

of external LEDs that can be connected depends on their operating power and forward

voltage drop, but typically 7 x 3.2V LEDs can be connected using a 28V rail. For an external

load other than LEDs, the positive terminal of the load should be connected to the anode and

the negative to the cathode.

2.

Connect VIN and GND.

Warning: The board does not have reverse battery/supply protection.

3.

Set the PSU to the desired input voltage (usually between 8V and 28V)

4.

Turn on the PSU. The external LEDs will illuminate and the current should be approximately

300mA

5.

The switching waveforms on the SW pin can be acquired using the test point J1

Warning: Do not stare at the LEDs directly.