Без темы
<<  Basic Asynchronous Network Algorithms Bible Class Atlas  >>
Battery Charger Design (1S): Key considerations and system design
Battery Charger Design (1S): Key considerations and system design
Agenda
Agenda
Single Cell Systems Overview
Single Cell Systems Overview
Input Considerations
Input Considerations
Adapter Power Limits
Adapter Power Limits
Current Capabilities of Adapters
Current Capabilities of Adapters
Voltage Input Dynamic Power Management (VINDPM)
Voltage Input Dynamic Power Management (VINDPM)
Voltage Input Dynamic Power Management (VINDPM)
Voltage Input Dynamic Power Management (VINDPM)
Power-path vs
Power-path vs
Dynamic Power-Path Management (DPPM)
Dynamic Power-Path Management (DPPM)
Dynamic Power-Path Management (DPPM)
Dynamic Power-Path Management (DPPM)
VINDPM and DPPM working together
VINDPM and DPPM working together
Does VINDPM = DPPM
Does VINDPM = DPPM
Thermal Regulation and Protection Loops
Thermal Regulation and Protection Loops
Factors affecting thermal performance (effects on
Factors affecting thermal performance (effects on
Product Thickness and Battery Size: Smartphones
Product Thickness and Battery Size: Smartphones
Working around tradeoffs…
Working around tradeoffs…
Charge Cycle
Charge Cycle
Charge Time Optimizer in Action – bq2426x
Charge Time Optimizer in Action – bq2426x
Extending Run Time on Power Path Chargers
Extending Run Time on Power Path Chargers
Summary
Summary
Questions
Questions

Презентация на тему: «Battery Charger Design (1S): Key considerations and system design limitations». Автор: Aguirre, Miguel. Файл: «Battery Charger Design (1S): Key considerations and system design limitations.pptx». Размер zip-архива: 847 КБ.

Battery Charger Design (1S): Key considerations and system design limitations

содержание презентации «Battery Charger Design (1S): Key considerations and system design limitations.pptx»
СлайдТекст
1 Battery Charger Design (1S): Key considerations and system design

Battery Charger Design (1S): Key considerations and system design

limitations

Miguel Aguirre October, 2012

1

2 Agenda

Agenda

Single Cell Charger Systems Input Considerations and Limitations Topology Options Pros & Cons of Power Path Architecture Thermal Issues Market Trends Needs vs. Limitations Charge Time Optimizer Summary and Questions

2

3 Single Cell Systems Overview

Single Cell Systems Overview

Single Cell Most Common Solution for Smartphones (1s) and Tablets (1sXp) today Allows for simple, low voltage design on the system (Max Battery Voltage 4.35V on some lithium based chemistries) Simple design to charge from a 5V supply as the charger will always operate in step down mode Multiple cells in parallel allow for longer run times due to extra capacity This will require a higher charge currents to maintain an acceptable charge time. Charge current will be a function of the current capability of the adapter.

3

4 Input Considerations

Input Considerations

How many input connectors will the device have? Single Input (i.e. Micro-USB, Proprietary Connector) Multiple Inputs (i.e. Micro-USB and Dock Connector) How many input sources will the product support? USB charging only (Max current: 500mA for USB2.0, 900mA for USB3.0) USB charging and/or adapter into single port For Micro-USB port, maximum current supported by adapter is 1.8A USB specifies maximum current of 1.5A With a limit on the current, changing the input voltage allows you to increase your output current USB Power Delivery (USBPD) will allow for more power available for charge solutions.

Output current change based on input voltage (assume 90% efficiency and 3.6V Battery)

4

5 Adapter Power Limits

Adapter Power Limits

Adapter Power Limits Today Most Smartphones: 5W – 8W Most Popular Tablets: 10W – 15W

5

6 Current Capabilities of Adapters

Current Capabilities of Adapters

Power sources have their limits There are situations where the input power source does not have enough power to supply what the portable device demands Becoming increasingly important with the standardization of input connectors such as the Micro-USB Input current limits and Input Voltage Dynamic Power Management (VINDPM) provide the functions needed to solve this problem

6

7 Voltage Input Dynamic Power Management (VINDPM)

Voltage Input Dynamic Power Management (VINDPM)

Utilizing full capacity of adapter – VIN Dynamic Power Management (VINDPM) Loop continuously monitoring the input voltage to the charger Without VINDPM the device can enter a hiccup mode between power up and “brown-out” condition When input voltage drops, device will limit the input current

Device hits VINDPM threshold and input current is reduced

7

8 Voltage Input Dynamic Power Management (VINDPM)

Voltage Input Dynamic Power Management (VINDPM)

Utilizing full capacity of adapter – VIN Dynamic Power Management (VINDPM) Loop continuously monitoring the input voltage to the charger Without VINDPM the device can enter a hiccup mode between power up and “brown-out” condition When input voltage drops, device will limit the input current

Programmed Charge current higher than adapter capability

Device hits VINDPM threshold and input current is reduced

8

9 Power-path vs

Power-path vs

Non Power-path Topologies

Non Power-Path Topology The system voltage is always equal to the battery voltage No system startup for deeply discharged batteries ICHARGE is always split between IBAT and ISYS ICHARGE must be programmed to the maximum charge current for the battery cell If ISYS > Termination current, then termination will not occur IBAT is reduced for any system load Reduced charge current extends charge time. Safety timers may expire prematurely

Power-Path Topology ICONVERTER is set to maximize the current from the source. More available current to system and battery charging for faster charge time IBAT is set independent of ICONVERTER For low system loads, ICONVERTER is reduced to maintain proper charge current IBAT is always known by charger Accurate termination current Safety timer extended when charge current is less than programmed value

ICONVERTER

ISYS

ICHARGE

ISYS

IBAT

IBAT

9

10 Dynamic Power-Path Management (DPPM)

Dynamic Power-Path Management (DPPM)

Function that monitors the input current, input voltage and output currents of a Power-Path device and automatically gives priority to the system when the adapter can not support the system load See following example of DPPM function in a linear charger. Same principle allies for switching chargers. Assume 5W adapter (5V, 1A)

ISYS=0.5A

IIN?1A

IBAT=0.5A

10

11 Dynamic Power-Path Management (DPPM)

Dynamic Power-Path Management (DPPM)

Function that monitors the input current, input voltage and output currents of a Power-Path device and automatically gives priority to the system when the adapter can not support the system load See following example of DPPM function in a linear charger. Same principle allies for switching chargers. Assume 5W adapter (5V, 1A)

ISYS=0.8A

IIN?1A

IBAT=0.2A

11

12 VINDPM and DPPM working together

VINDPM and DPPM working together

VIN 5V Adapter rated for 750mA

IIN

VSYS

IBAT

ISYS

Adapter Voltage Falls due to Adapter Current Limit

Input Current Reduced by VINDPM function to Prevent Adapter from Crashing

750mA Charging

750mA Charging

Supplement Mode

1.2A Load Step

13 Does VINDPM = DPPM

Does VINDPM = DPPM

No. VINDPM prevents the adapter from hitting a “brown-out” condition. However, the charger will not know how much current is going to the system and how much current is going to the battery. A charger can have VINDPM and not have Power-path (DPPM) Charge current and system current is combined and the charger does not know how much current is being delivered only to the battery DPPM allows the charger to know exactly how much current is going to the battery. With this information, the charger can reduce the charge current and extend the charging safety timer in the even the system demands higher currents Which one is better? Both topologies allow to charge the battery. Non DPPM chargers will require the host to measure exactly how much current goes to the battery for proper termination

13

14 Thermal Regulation and Protection Loops

Thermal Regulation and Protection Loops

Thermal management functions: Regulate IC junction temperature by reducing charge current , AND Turn off the charger when IC junction temperature is excessive Slow down the safety timers when the charge current is reduced by the thermal loop, avoiding a false safety timer fault Common implementations: The IC junction temperature is regulated to a value just below the maximum operating junction temperature, 1250C typical The charger is turned off when the Charger IC junction temperature is excessive, 1500C typical

PLOSS = (VIN – VBAT) * ICHG

14

15 Factors affecting thermal performance (effects on

Factors affecting thermal performance (effects on

JA)

Case Study: Thermal Effect of PCB design on ?JA Device Size: 2.1mm x 2mm, WCSP High K board (no vias), ?JA = 69 C/W Using 2x2 vias, ?JA = 45.4 C/W

EIA/JESD 51-1 Standard

15

16 Product Thickness and Battery Size: Smartphones

Product Thickness and Battery Size: Smartphones

HTC One X: 1800mAh, 8.9mm Samsung Galaxy S3: 2100mAh, 8.6mm Samsung Galaxy Note: 2500mAh, 10.1mm

HTC One X Battery ? 4.4mm thick Galaxy S3 Battery ? 5mm thick Galaxy Note Battery ? 6mm thick

Source: TechInsights Teardowns (web)

Programmed Charge current higher than adapter capability

Device hits VINDPM threshold and input current is reduced

16

17 Working around tradeoffs…

Working around tradeoffs…

Increasing Battery Size ? Larger Charge Current Decreasing product thickness ? Thinner Inductors ? Lower Charge Currents 2A – 3A charge current provides sweet spot of short charge times with acceptable inductor sizes Design for 1.5uH converter stability. Tradeoff between efficiency and inductor size Focus on charge time improvements (i.e. Charge Time Optimizer Feature)

3A Inductor 1.2mm height

2A Inductor 1.0mm height

4A Inductor 2mm height

17

18 Charge Cycle

Charge Cycle

No CTO

83mV Overlap Charge current reduces too early

18

19 Charge Time Optimizer in Action – bq2426x

Charge Time Optimizer in Action – bq2426x

Charge Time Optimizer Sharp handoff of CC and CV. Approximately 6mV overlap – Best in industry Reduces charge time!

For ITERM = 50mA ? Total Charge Time ~4:30 hrs For ITERM = 250mA ? Total Charge Time ~ 3:50 hrs For ITERM = 500mA (<0.1C) ? Total Charge Time ~ 3:10 hrs

19

20 Extending Run Time on Power Path Chargers

Extending Run Time on Power Path Chargers

Only 11 m?

Optional External FET Driver

20

21 Summary

Summary

Charger solutions greater than 3A on smartphones increases the thickness of the design. Thermal management is a problem with charge currents greater than 3A. Not enough board space to extract the heat generated on the charger. Focus on reducing charge times with Charge Time Optimizer on newer TI chargers (bq2425x, bq2426x) Increasing run time by reducing battery discharge path impedance (11 m? on bq2426x).

21

22 Questions

Questions

22

«Battery Charger Design (1S): Key considerations and system design limitations»
http://900igr.net/prezentacija/anglijskij-jazyk/battery-charger-design-1s-key-considerations-and-system-design-limitations-133123.html
cсылка на страницу

Без темы

661 презентация
Урок

Английский язык

29 тем
Слайды
900igr.net > Презентации по английскому языку > Без темы > Battery Charger Design (1S): Key considerations and system design limitations