bq24600 Stand-Alone Synchronous Switch-Mode Li-Ion or Li-Polymer Battery Charger with Low Iq

1 Features

1.2-MHz NMOS-NMOS Synchronous Buck Converter
Stand-Alone Charger Support for Li-Ion or Li-Polymer
5-V – 28-V VCC Input Voltage Range and Supports 1S-6S Battery Cells
Up to 10-A Charge Current and Adapter Current
High-Accuracy Voltage and Current Regulation
- ±0.5% Charge-Voltage Accuracy
- ±3% Charge-Current Accuracy
Integration
- Internal Loop Compensation
- Internal Soft Start
Safety
- Input Overvoltage Protection
- Battery Thermistor Sense Hot/Cold Charge Suspend
- Battery Detection
- Built-In Safety Timer
- Charge Overcurrent Protection
- Battery Short Protection
- Battery Overvoltage Protection
- Thermal Shutdown
Status Outputs
- Adapter Present
- Charger Operation Status
Charge Enable Pin
6-V Gate Drive for Synchronous Power Converter
30-ns Driver Dead-Time and 99.5% Max. Effective Duty Cycle
16-Pin 3.5-mm × 3.5-mm QFN package
Energy Star Low Quiescent Current I_q
- < 15-μA Off-State Battery Discharge Current
- < 1.5-mA Off-State Input Quiescent Current

2 Applications

Portable Equipment Handle Terminals
Industrial and Medical Equipment
Power Tools Appliance
Mobile Internet Device, and Ultra-Mobile PC

3 Description

The bq24600 is a highly integrated Li-ion or Li-polymer switch-mode battery-charge controller. It offers a constant-frequency synchronous PWM controller with high-accuracy charge current and voltage regulation, charge preconditioning, termination, and charge status monitoring,

The bq24600 charges the battery in three phases: preconditioning, constant current, and constant voltage. Charge is terminated when the current reaches a minimum level. An internal charge timer provides a safety backup. The bq24600 automatically restarts the charge cycle if the battery voltage falls below an internal threshold, and enters a low-quiescent-current sleep mode when the input voltage falls below the battery voltage.

Device Information⁽¹⁾

PART NUMBER	PACKAGE	BODY SIZE (NOM)
bq24600	VQFN (16)	3.50 mm x 3.50 mm

For all available packages, see the orderable addendum at the end of the datasheet.

Simplified Schematic

4 Revision History

Changes from A Revision (October 2011) to B Revision

Changed Added Handling Rating table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Device and Documentation Go
Changed feature text From: "Supports 1-6 Battery Cells" To: "Supports 1S-6S Battery Cells"Go
Changed the Application list Go
Deleted the Table of Graphs from the Typical Characteristics section Go
Changed the Description of D3, D4 in Table 4 From: "LED diode, green, 2.1 V, 10 mΩ, Vishay-Dale, WSL2010R0100F" To:"LED diode, green, 2.1 V, 20 mA, LTST-C190GKT"Go

Changes from * Revision (February 2010) to A Revision

Changed descriptions of PH and BTST pins in Pin Description tableGo
Changed V_HTF to V_TCO in two places in Equation 5Go
Changed Equation 15Go

5 Pin Configuration and Functions

RVA Package

(Top View)

Pin Functions

PIN		I/O	FUNCTION DESCRIPTION
NAME	NO.	I/O	FUNCTION DESCRIPTION
VCC	1	I	IC power positive supply. Connect, through a 10-Ω resistor to the common-source (diode-OR) point: source of high-side P-channel MOSFET and source of reverse-blocking power P-channel MOSFET. Or connect through a 10-Ω resistor to the cathode of the input diode. Place a 1-μF ceramic capacitor from VCC to the GND pin close to the IC.
CE	2	I	Charge-enable active-HIGH logic input. HI enables charge. LO disables charge. It has an internal 1MΩ pull-down resistor.
STAT	3	I	Open-drain charge status pin to indicate various charger operation (See Table 2)
TS	4	I	Temperature qualification voltage input for battery pack negative temperature coefficient thermistor. Program the hot and cold temperature window with a resistor divider from VREF to TS to GND.
PG	5	O	Open-drain power-good status output. The transistor turns on when a valid VCC is detected. It is turned off in the sleep mode. PG can be used to drive an LED or communicate with a host processor. It can be used to drive ACFET and BATFET.
VREF	6	O	3.3-V regulated voltage output. Place a 1-μF ceramic capacitor from VREF to the GND pin close to the IC. This voltage could be used for programming of voltage and current regulation and for programming the TS threshold.
ISET	7	I	Charge current set input. The voltage of ISET pin programs the charge current regulation, pre-charge current and termination current set-point.
VFB	8	O	Output voltage analog feedback adjustment. Connect the output of a resistive voltage divider from the battery terminals to this node to adjust the output battery regulation voltage.
SRN	9	I	Charge-current sense resistor, negative input. A 0.1-μF ceramic capacitor is placed from SRN to SRP to provide differential-mode filtering. An optional 0.1-μF ceramic capacitor is placed from SRN pin to GND for common-mode filtering.
SRP	10	I	Charge-current sense resistor, positive input. A 0.1-μF ceramic capacitor is placed from SRN to SRP to provide differential-mode filtering. A 0.1-μF ceramic capacitor is placed from SRP pin to GND for common-mode filtering.
GND	11	--	Low-current sensitive analog/digital ground. On PCB layout, connect with thermal pad underneath the IC.
REGN	12	O	PWM low-side driver positive 6-V supply output. Connect a 1-μF ceramic capacitor from REGN to the PGND pin, close to the IC. Use for low-side driver and high-side driver bootstrap voltage by connecting a small-signal Schottky diode from REGN to BTST.
LODRV	13	O	PWM low-side driver output. Connect to the gate of the low-side power MOSFET with a short trace.
PH	14	I	PWM high-side driver negative supply. Connect to the phase-switching node (junction of the low-side power MOSFET drain, high-side power MOSFET source, and output inductor).
HIDRV	15	O	PWM high-side driver output. Connect to the gate of the high-side power MOSFET with a short trace.
BTST	16	I	PWM high-side driver negative supply. Connect the 0.1-μF bootstrap capacitor from PH to BTST, and a bootstrap Schottky diode from REGN to BTST.
Thermal pad	--	--	Exposed pad beneath the IC. Always solder thermal pad to the board, and have vias on the thermal pad plane star-connecting to GND and ground plane for high-current power converter. It also serves as a thermal pad to dissipate the heat.