Texas Instruments TPS60230EVM-047 Setup, Operation, Relative LED Current Levels, Test Results

Input/Output Connector Descriptions

2.2Setup

Connect an input supply or battery between J1 and J2. The voltage range on this supply should stay between 2.7V and 6.0V. Set the appropriate brightness by configuring JP1 and JP2.

2.3Operation

The EVM has been optimized to operate from a single-cell Li-Ion battery with an input voltage range of 2.7V to 6.0V. The value for R1 programs the maxi- mum LED current. For this EVM, the maximum current is set to 20mA. Howev- er, by changing the value of R1, LED currents up to 25mA can be achieved. Currents less than 20mA can be achieved by appropriately configuring JP1 and JP2, as shown in Table 1.

Table 1. Relative LED Current Levels

JP1 (EN2)	JP2 (EN1)	LED CURRENT
0	0	0
0	1	1/3 full
1	0	2/3 full
1	1	Full (20mA for R1 = 7.87kΩ)

EN1 and EN2 can also be used for pulse width modulator (PWM) dimming. The PWM signal can be applied to EN1, EN2, or both. In this case, the LED current is proportional to duty factor and can have a maximum current dictated by how EN1 and EN2 are configured. The maximum recommended PWM fre- quency is 50kHz, and the minimum recommended ON time is 2.5us. Refer to the datasheet (SLVS516) for more information in regards to PWM dimming.

2.4Test Results

The efficiency curve in Figure 1 reflects the power delivered to the LED. The output power used for the efficiency calculation is the sum of all the LED cur- rents multiplied by the LED forward voltage.

Figure 1. Efficiency vs VIN

Efficiency (%)

90

80

70

60

50

40

30

20

10

0

EN2 and EN1 = On

ILED = 20mA

2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 5.9 6.3 6.5

Input Voltage (V)

TPS60230EVM-0473