Electronic component search and free download site.
Transistors,MosFET ,Diode,Integrated circuits

BQ25504 View Datasheet(PDF) - Texas Instruments

Part NameDescriptionManufacturer
BQ25504 Ultra Low-Power Boost Converter With Battery Management for Energy Harvester Applications Texas-Instruments
Texas Instruments Texas-Instruments
BQ25504 Datasheet PDF : 36 Pages
First Prev 21 22 23 24 25 26 27 28 29 30 Next Last
www.ti.com
Typical Applications (continued)
9.2.2 TEG Application Circuit
bq25504
SLUSAH0C – OCTOBER 2011 – REVISED JUNE 2015
Thermo electric
generator
L BST
22µH
CHVR
4.7µF
CBYP (1)
CSTOR(2)
4.7 µF
(min)
Battery(>100µF)
VSTOR
16 15 ` 14
LBST VSTOR
1 VSS
VBAT
13
VSS
AVSS 12
ROC 2
10 MΩ
ROC 1
10 MΩ
2 VIN_DC
VBAT_OK 11
bq25504
3 VOC_SAMP
OK_PROG 10
CREF
4 VREF _SAMP
OK_HYST 9
0.01µF
OT_PROG VBAT_OV VRDIV VBAT_UV
5
6
7
8
VSTOR
ROV2
5.62MΩ
ROV1
4.42MΩ
RUV 2
6.12MΩ
RUV 1
3 .83MΩ
ROK1
3.32 MΩ
ROK2
6.12 MΩ
ROK3
542 kΩ
VBAT_OK
(1) Place close as possible to IC pin 15 (VSTOR) and pin 13 (VSS)
(2) See the Capacitor Selection section for guidance on sizing CSTOR
Figure 21. Typical TEG Application Circuit
9.2.2.1 Design Requirements
The desired voltage levels are VBAT_OV = 4.25 V, VBAT_UV = 3.20 V, VBAT_OK = 3.55 V, VBAT_OK_HYST =
3.76 V and MPP (VOC) = 50% which is typical for TEG harvesters. The IC must stop charging if its junction
temperature is above 120°C. The simulated TEG open circuit voltage is 1.0 V.
9.2.2.2 Detailed Design Procedure
The recommended L1 = 22 µH, CBYP = 0.01 µF and low leakage CREF = 10 nF are selected. In order to ensure
the fastest recovery of the harvester output voltage to the MPPT level following power extraction, the minimum
recommended CIN = 4.7 µF is selected. Because no large system load transients are expected and to ensure
fast charge time during cold start, the minimum recommended CSTOR = 4.7 µF. To stop charging when the IC
junction temperature is above 120°C, the OT_PROG pin is tied to VSTOR.
Referring back to the procedure in Detailed Design Procedure or using the spreadsheet calculator at SLURAQ1
gives the following values:
• ROV1 = 4.42 M, ROV2 = 5.49 Mresulting in VBAT_OV = 4.26 V due to rounding to the nearest 1% resistor.
• RUV1 = 3.83 M, RUV2 = 6.04 Mresulting in VBAT_UV = 3.22 V due to rounding to the nearest 1% resistor
• ROK1 = 3.32 M, ROK2 = 6.04 M, ROK3 = 0.536 Mresulting in VBAT_OK = 3.52 V and
VBAT_OK_HYST = 3.73 V after rounding.
• ROC1 = 10 Mand ROC2 = 10 Mgives 50% MPP voltage.
Copyright © 2011–2015, Texas Instruments Incorporated
Product Folder Links: bq25504
Submit Documentation Feedback
21
Direct download click here

 

Share Link : 
All Rights Reserved© datasheetq.com 2015 - 2020  ] [ Privacy Policy ] [ Request Datasheet  ] [ Contact Us ]