CYRF69103_11 Datasheet, PDF (10/68 Pages) Cypress Semiconductor – Programmable Radio on Chip Low Power 16-bit free running timer

CYRF69103
The PMU also provides a configurable low battery detection
function which may be read over the SPI interface. One of seven
thresholds between 1.8V and 2.7V may be selected. The
interrupt pin may be configured to assert when the voltage on the
V_BAT pin falls below the configured threshold. LV IRQ is not a
latched event. Battery monitoring is disabled when the device is
in sleep mode.
The following three figures show different examples of how to
use PRoC LP with and without the PMU. Figure 8-2. shows the
most common circuit making use of the PMU to boost battery
voltage up to 2.7V. Figure 8-3. is an example of the circuit used
when the supply voltage is always above 2.7V. This could be
three 1.5V battery cells in series along with a linear regulator, or
some similar power source. Figure 8-4. shows an example of
using the PRoC LP with its PMU disabled and an external boost
to supply power to the device. This might be required when the
load is much greater than the 15 mA average load that PRoC can
support.
Figure 8-2. PMU Enabled
VBat
VCC
1 Ohm 1%
47 Ohm
10 µF
6.3V
1 µF
6.3V
0.047 µF
0.047 µF
0.047 µF
0.047µF
0.047 µF
0.047 µF
Figure 8-3. PMU Disabled - Linear Regulator
VCC
0.047µF
0.047µF
0.047µF
0.047µF
0.047µF
0.047µF
0.047µF
0.047µF
VDD
VDD_MICRO
0.1µF
PRoC LP
Figure 8-4. PMU Disabled - External Boost Converter
VCC External DC-DC
VBat
Boost Converter
VDD
VDD_MICRO
0.1µF
PRoC LP
VBat
VCC
100 µF 10V
10 µH BAT400D
10 µF 6.3V
1 Ohm 1%
47 Ohm
10µF
6.3V
1µF
6.3V
0.047µF
0.047µF
0.047µF
0.047µF
0.047µF
0.047µF
VDD
VDD_MICRO
PRoC LP
0.1µF
Document #: 001-07611 Rev *F
Page 10 of 68
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