isl88731c Intersil Corporation, isl88731c Datasheet - Page 5

• Manufacturer Part Number: isl88731c
• Description: Smbus Level 2 Battery Charger
• Manufacturer: Intersil Corporation

Table of Contents
Absolute Maximum Ratings .............................. 6
Thermal Information ........................................ 6
Electrical Specifications .................................... 6
SMBus Timing Specifications ............................ 8
Theory of Operation......................................... 11
Byte Format..................................................... 13
ISL88731C and SMBus..................................... 13
Battery Charger Registers ............................... 14
Enabling and Disabling Charging ..................... 14
Setting Charge Voltage .................................... 14
Setting Charge Current .................................... 15
Setting Input-Current Limit ............................. 16
Charger Timeout.............................................. 17
ISL88731C Data Byte Order............................. 17
Introduction .................................................. 11
PWM Control.................................................. 11
AC-Adapter Detection ..................................... 11
Current Measurement ..................................... 11
VDDP Regulator ............................................. 11
VDDSMB Supply............................................. 11
Short Circuit Protection and 0V Battery Charging 11
Undervoltage Detect and Battery Trickle Charging..... 12
Over-Temperature Protection........................... 12
Overvoltage Protection.................................... 12
The System Management Bus .......................... 12
General SMBus Architecture ............................ 12
Data Validity ................................................. 12
START and STOP Conditions................................ 12
Acknowledge..................................................... 13
SMBus Transactions ........................................... 13
5
ISL88731C
Writing to the Internal Registers .................... 17
Reading from the Internal Registers ............... 17
Application Information .................................. 17
PCB Layout Considerations.............................. 22
Revision History .............................................. 24
Products.......................................................... 24
Package Outline Drawing ............................... 25
Inductor Selection ......................................... 17
Output Capacitor Selection ............................. 18
MOSFET Selection.......................................... 18
Snubber Design............................................. 19
Input Capacitor Selection................................ 19
Loop Compensation Design ............................. 19
Transconductance Amplifiers GMV, GMI and GMS ..... 19
PWM Gain Fm ............................................... 19
Charge Current Control Loop........................... 20
Adapter Current Limit Control Loop .................. 20
Voltage Control Loop...................................... 21
Output LC Filter Transfer Functions .................. 21
Compensation Break Frequency Equations ........ 22
Power and Signal Layers Placement on the PCB . 22
Component Placement ................................... 22
Signal Ground and Power Ground Connection .... 23
GND and VCC Pin .......................................... 23
LGATE Pin .................................................... 23
PGND Pin ..................................................... 23
PHASE Pin .................................................... 23
UGATE Pin .................................................... 23
BOOT Pin...................................................... 23
CSOP, CSON, CSSP and CSSN Pins .................. 23
DCIN Pin ...................................................... 23
Copper Size for the Phase Node....................... 23
Identify the Power and Signal Ground .............. 23
Clamping Capacitor for Switching MOSFET ........ 23
September 9, 2010
FN6978.1