Datasheet

Efficiency
2-8
2.7 Efficiency
Figure 2−4 shows the measured efficiency of the TPS61040.
Figure 2−4. Typical Efficiency
80
81
82
83
84
85
86
87
88
89
90
2.5 5 7.5 10 12.5 15 17.5 20
V
I
= 6 V
V
I
= 4.2 V
V
I
= 3.6 V
V
I
= 2.5 V
Efficiency %
I
O
− Output Current − mA
2.8 Analog Dimming With Analog Voltage Data
The EVM was modified to generate a 0 mA to 20 mA output when the control
voltage is varied from 3.3 V to 0 V. The appropriate component values may be
calculated using the equations provided in the Analog Dimming with Analog
Voltage section. Using the closest standard values available, R2 = 249 kΩ,
R3 = 147 kΩ, and R4 = 100 Ω. Figure 2−5 shows the linear relationship
between the output current and the control voltage injected into DIM1.
Figure 2−5. Output Current vs Control Voltage
0
5
10
15
20
01 2 3
Control Voltage − V
Diode Current − mA