Integration Manual

SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R13 Design-in Page 48 of 119
C5C3 C6
GND
SARA-R4/ N4
52
VCC
53
VCC
51
VCC
USB
Supply
θ
U1
PG
STAT 2
STA1
VDD
C1
5V0
THERM
Vss
Vbat
Li-Ion/Li-Pol
Bat t ery Pack
D1
B1
C2
Li-Ion/Li-Polym er
Bat t ery Charger IC
D2
PROG
R1
C4
Figure 22: Li-Ion (or Li-Polymer) battery charging application circuit
Reference Description Part Number - Manufacturer
B1
Li-Ion (or Li-Polymer) battery pack with 470 Ω NTC
Generic manufacturer
C1 1 µF Capacitor Ceramic X7R 16 V Generic manufacturer
C2
100 µF Capacitor Tantalum B_SIZE 20% 6.3V 15mΩ
T520B107M006ATE015 – Kemet
C3 15 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H150JA01 - Murata
C4 68 pF Capacitor Ceramic C0G 0402 5% 50 V GRM1555C1H680JA01 - Murata
C5 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata
C6 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 - Murata
D1, D2 Low Capacitance ESD Protection CG0402MLE-18G - Bourns
R1
10 kΩ Resistor 0.1 W
Generic manufacturer
U1 Single Cell Li-Ion (or Li-Polymer) Battery Charger IC MCP73833 - Microchip
Table 15: Suggested components for the Li-Ion (or Li-Polymer) battery charging application circuit
☞
☞☞
☞ See the section 2.2.1.10, and in particular Figure 27 / Table 19, for the parts recommended to be provided if the
application device integrates an internal antenna.
2.2.1.7 Guidelines for external charging and power path management circuit
Application devices where both a permanent primary supply / charging source (e.g. ~12 V) and a rechargeable back-up
battery (e.g. 3.7 V Li-Pol) are available at the same time as a possible supply source, should implement a suitable charger
/ regulator with integrated power path management function to supply the module and the whole device while
simultaneously and independently charging the battery.
Figure 23 reports a simplified block diagram circuit showing the working principle of a charger / regulator with integrated
power path management function. This component allows the system to be powered by a permanent primary supply
source (e.g. ~12 V) using the integrated regulator, which simultaneously and independently recharges the battery (e.g.
3.7 V Li-Pol) that represents the back-up supply source of the system. The power path management feature permits the
battery to supplement the system current requirements when the primary supply source is not available or cannot deliver
the peak system currents.
A power management IC should meet the following prerequisites to comply with the module VCC requirements
summarized in Table 6:
• High efficiency internal step down converter, with characteristics as indicated in section 2.2.1.2
• Low internal resistance in the active path Vout – Vbat, typically lower than 50 mΩ
• High efficiency switch mode charger with separate power path control