Texas Instruments UCC2977EVM - Manual (Page 21)

Test Setup
3-3 Test Results
3.1.2 Analog Dimming Test
For analog dimming, enable the open-lamp detection by connecting pin 1 to
pin 2 of jumper JP1. A power supply that has a power capability of 6 V/0.5 A
is required for this test. Figure 3–2 shows the input/output connections to the
SLUP178. The lamp intensity is controlled by V
AD
(0~3 Vdc). Make sure the
wire of the lamp is as short as possible and the lamp reflector (if there is one)
is grounded to board ground. Do not let the high voltage wire cross any part
of the board.
Figure 3–2. Test Setup for Analog Dimming
Power Supply
Power Supply
CCFL
Lamp