Output Load (A)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
2 Layer, 15 mils
2 Layer, 62 mils
2 Layer, 31 mils
2 Layer, 24 mils
OTG Output V
oltage (V)
5.2
5.15
5.1
5.05
5
4.95
4.9
4.85
4.8
4.75
4 Layer, 2 x 15 mils
Introduction
1
Introduction
1.1
EVM Features
Refer to the data sheet (
) for detailed features and operation.
1.2
Design Considerations
1. Install the JP1 shunt for proper operation.
2. Disable the watchdog timer if not using the
WDG Timer Reset
button (illustrated in
), so the
programmed setting does not reset.
3. The GUI STATUS and FAULT block are helpful in troubleshooting, if the design is having issues.
4. In Boost mode, if not using a battery or power supply with short leads, extra capacitance at J5
(BAT/GND) may be needed.
5. The
OTG Low
box has to be unchecked and the
Enable OTG
box must be checked to get into Boost
mode.
6. PWB thickness affects the “On-the-GO” (OTG) Boost Output regulation at load currents over 0.75 A.
An evaluation was performed using different thicknesses of PCBs with the Load Regulation results
shown in
TI recommends using a 4-layer PCB constructed with two 15-mil, 2-oz Cu/layer boards fixed together,
for a total thickness of 31 mils. The 4-layer PCB, has a stack up of a component/routing layer, GND
layer, routing layer and a GND layer. A second choice is a 2-layer, 24-mil PCB, or thinner, with a
component/routing layer and a GND plane layer. The bq24295EVM-549 REV B EVM is built on a 24-
mil thick PCB.
Figure 1. OTG Boost Mode 5-V Output Load Regulation Versus PCB Layer Thickness - Default Setting
1.3
General Descriptions
The bq24295 evaluation module is a complete charger module for evaluating an I
2
C Controlled single
NVDC-1 charge using the bq2419x devices. For details, see bq24295 data sheet (
The bq24295 EVM doesn’t include the USB-to-GPIO interface board. To evaluate the bq24295 EVM, the
USB-to-GPIO interface board must be ordered separately. Search ti.com for "USB-to-GPIO".
2
bq24295EVM-549 (PWR549) User’s Guide
SLUUAO5B – August 2013 – Revised April 2014
Copyright © 2013–2014, Texas Instruments Incorporated
