Texas Instruments bq24072, User Manual

Page: 3 / 22

www.ti.com
Performance Specification Summary
3 SLVU274E – November 2008 – Revised January 2017
Submit Documentation Feedback
Copyright © 2008–2017, Texas Instruments Incorporated
bq24072/3/4/5/9(T) and bq24230/2 1.5-A Single-Chip Li-Ion and Li-Polymer
Charge Management IC EVM
The two potential sources to power the system (V
OUT
) are the input source and the battery (adapter or
USB port). The IC is designed to power the system continuously. The battery, in most cases, is the last
line of backup. If the adapter/USB input is not available (or disabled), the battery connects to the system.
In thermal regulation condition (T
J
= 125°C not a first-choice design mode of operation), the charge current
is reduced to the battery, and the system still gets its power from the input. The battery supplement is
available in thermal regulation if the V
OUT
falls to V
BAT
. In thermal cutoff (~155°C), the input sources are
disconnected, but the internal battery FET connects the battery to V
OUT
.
3 Performance Specification Summary
Table 2 summarizes the performance specifications of the EVM.
(1)
The HPA073 (bq24072/3/4/5/9(T) and bq24230/2) thermal design is optimized (8
+
vias, 0.031-inch PCB, 2-oz. copper) to give
θ
JA
~ 27°C/W.
Table 2. Performance Specification Summary for bq24072/3/4/5/9(T) and bq24230/2 EVMs
SPECIFICATION TEST CONDITIONS MIN TYP MAX UNITS
Input dc Voltage, V
I(AC)
4.75 5 6.5 Volts
Battery Charge Current, I
O(CHG)
1 1.5 Amperes
Power Dissipation, bq24072/3/4/5/9(T) and bq24230/2
IC, 1 Cell Pdiss = (Vin-Vout)Iout +(Vin-Vbat)Ibat See
(1)
Watts
3.1 Performance Recommendations
This IC is a linear battery charger and also powers the system from the input via the linear regulator
output. The key here is that this is a linear device that is most efficient when the input voltage is not too far
above the battery voltage (Vin = 4.75 V to 5.5 V). Too low of input voltage (less than the OUT voltage plus
the dropout voltage) results in degraded performance. Excessive input voltage (>5.5 V) results in excess
power dissipation and reduced performance via thermal regulation. The IC is rated to 28 V, and will not be
damaged with Vin voltages less than this, but any Vin voltage over the overvoltage protection (OVP)
threshold disables the IC. Thus, the recommended operating range for maximum performance is between
4.75 V and 5.5 V, with a preference toward the lower values.