BQ25505 Datasheet, PDF (7/34 Pages) Texas Instruments – Ultra Low Power Boost Charger with Battery Management and Autonomous Power

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DEVICE INFORMATION
bq25505
SLUSBJ3B – AUGUST 2013 – REVISED JANUARY 2014
RGT PACKAGE
(TOP VIEW)
20 19 18 17 16
VSS 1
VIN_DC 2
VOC_SAMP 3
VREF_SAMP 4
EN 5
bq25505
RGR
3.5x3.5mm
15 VSS
14 VBAT_PRI
13 VBAT_OK
12 _{OK_PROG}
11 _{OK_HYST}
6
7
8
9 10
PIN
NO.
NAME
1
VSS
2
VIN_DC
3
VOC_SAMP
4
VREF_SAMP
5
EN
6
NC
7
VBAT_OV
8
VRDIV
9
VB_SEC_ON
10
VB_PRI_ON
11
OK_HYST
12
OK_PROG
13
VBAT_OK
14
VBAT_PRI
15
VSS
16
NC
17
NC
18
VBAT_SEC
19
VSTOR
20
LBOOST
Figure 1. bq25505 3.5mm x 3.5mm QFN-20 Package
I/O TYPE
Input
Input
Input
Input
Input
Input
Output
Output
Output
Input
Input
Output
Input
Supply
Input
Input
I/O
Output
Input
PIN FUNCTIONS
DESCRIPTION
General ground connection for the device
DC voltage input from energy harvesters. Connect at least a 4.7 µF capacitor as close as possible
between this pin and pin 1.
Sampling pin for MPPT network. Connect to VSTOR to sample at 80% of input soure open circuit
voltage. Connect to GND for 50% or connect to the mid-point of external resistor divider between
VIN_DC and GND.
Sample and hold circuit output for the reference set by the MPPT per VOC_SAMP. Connect a 0.01 µF
capacitor from this pin to GND.
Active low digital programming input for enabling/disabling the IC. Connect to GND to enable the IC.
Connect to VSS via the IC's PowerPad.
Connect to the mid-point of external resistor divider between VRDIV and GND for setting the
VBAT_SEC overvoltage threshold.
Connect high side of resistor divider networks to this biasing voltage.
Active low push-pull driver for the secondary (rechargeable) energy storage PMOS FET.
Active low push-pull driver for the primary (non-rechargeable) energy storage PMOS FET.
Connect to the mid-point of external resistor divider between VRDIV and GND for setting the
VBAT_OK hysteresis threshold.
Connect to the mid-point of external resistor divider between VRDIV and GND for setting the
VBAT_OK threshold.
Digital output for battery good indicator. Internally referenced to the VSTOR voltage.
Primary (non-rechargeable) energy storage element HiZ sense input.
Signal ground connection for the device.
Connect to ground using the IC's PowerPad.
Connect to ground using the IC's PowerPad.
Connect a secondary (rechargeable) storage element with at least 100uF of equivalent capacitance to
this pin.
Connection for the output of the boost charger. Connect at least a 4.7 µF capacitor in parallel with a
0.1 µF capacitor as close as possible to between this pin and pin 1 (VSS).
Inductor connection for the boost charger switching node. Connect a 22 µH inductor between this pin
and pin 2 (VIN_DC).
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