STMicroelectronics LED7707, Application Note, Page: 8 / 17

I/O interface AN2810
8/17 Doc ID 14893 Rev 1
5 I/O interface
The LED7707 demonstration board is equipped with the test points described in Table 3.
6 Recommended equipment
●
4.5 V to 32 V, 2 A capable power supply
● Digital multi-meters
●
20 MHz oscilloscope
● Signal generators for PWM dimming and synchronization clock (optional)
7 Configuration
The LED7707 demonstration board allows the user to choose the desired mode of operation
using the SW1 and SW2 selectors (refer to the configuration description in the following
paragraphs). A red LED is connected to the FAULT pin to easily monitor its status; if this
option is not required, the monitor LED can be disconnected opening the J2 jumper.
7.1 SW1 fixed or adjustable switching frequency (FSW pin)
The SW1 selector is used to choose between the fixed switching frequency (660 kHz) and a
user-defined switching frequency in the range 250 kHz to 1 MHz (see
Figure 5 ). When
placed in the “down” position, the fixed switching frequency is selected.
Table 3. LED7707 demonstration board test points description
Test point Description
VIN+ Input voltage, positive terminal
VIN- Input voltage, negative terminal
GND Reference ground
ROW1 to ROW6 Current generator output
VBOOST Boost regulator output voltage
DIM PWM dimming input
EN Enable input (active high)
SYNC Synchronization output
FSW Synchronization input
FAULT Fault signal, active low