EVAL6924D

EVAL6924D EVAL6924D Battery charger system with integrated Power Switch for Li-ION/Li-POLYMER Data Brief General description many parameters, such as pre-charge current, fast-charge current, pre-charge voltage threshold, end-of-charge current threshold, and charge timer. The L6924D is a fully monolithic battery charger dedicated to single-cell Li-Ion/Polymer battery packs. It is the ideal solution for space-limited applications, like PDAs, handheld equipment, cellular phones, and digital cameras. It is designed with BCD6 technology and integrates all of the power elements (the Power MOSFET, reverse blocking diode and the sense resistor) in a small VFQFPN16 3mm x 3mm package. ) s ( t c u d o ) r s ( P t c e t u e d l o o r s P b e O t e l ) o s ( s t b c u O d o ) r s P ( t c e t u e l d o o r s P b O e t e l o s b O The L6924D offers two open collector outputs for diagnostic purposes, which can be used to either drive two external LEDs or communicate with a host microcontroller. Finally, the L6924D also provides very flexible control of the charge process termination and Gas Gauge capability, as well as other functions, such as checking for battery presence, and monitoring and protecting the battery from unsafe thermal conditions. When an external voltage regulated wall adapter is used, the L6924D works in Linear Mode, and charges the battery in a Constant Current/Constant Voltage (CC/CV) profile. Moreover, when a current-limited adapter is used, the device can operate in Quasi-Pulse Mode, dramatically reducing the power dissipation. Regardless of the charging approach, a closed loop thermal control avoids device overheating. The EVAL6924D Evaluation Board integrates the linear battery charger as well as the external components required for a typical application. The input voltage range can be adjusted between 2.5V and 12V, while the output voltage is selected by J4, between 4.1V and 4.2V, depending on the battery type. The fast charge current is set to 500 mA through the 24K R5 resistor. The device has an operating input voltage ranging from 2.5V to 12V and it allows the user to program Evaluation board November 2006 Rev 1 For further information contact your local STMicroelectronics sales office. 1/4 www.st.com 4 Features 1 EVAL6924D Features Figure 1. Evaluation board schematic R9 R3 C4 CHARGER V IN NTC V REF TH V OUT V INSNS R1 BATTERY V OSNS C1 IEND R2 T PRG C2 LD1 IPRG L6924D C3 LD2 R4 ) s ( t c u d o ) r s ( P t c e t u e d l o o r s P b e O t e l ) o s ( s t b c u O d o ) r s P ( t c e t u e l d o o r s P b O e t e l o s b O J2 ST2 V PRE ST1 R5 J5 J1 SHDN GND V OPRG IPRE R6 J3 R10 J4 ∝C Vref R7 Table 1. Name 2/4 R8 Evaluation board part list Value Description R1 1K Pull up resistor. To be used when the ST1s connected with a LED R2 1K Pull up resistor. To be used when the ST1s connected with a LED R3 1K Pull up resistor. Connected between VREF and TH pin R4 3K3 End of charge current resistor. Used to set the termination current and, as a “Gas Gauge“ when measuring the voltage across on it. R5 24K Fast-charge current resistor. Used to set the charging current R6 N.M VPRETH resistor. Used to set programmable pre-charge voltage threshold. If not mounted, the VPRETHDefault, equal to 2.8V, is set R7 N.M IPRETH resistor. Used to set programmable pre-charge voltage threshold below the default one. If not mounted, the IPRETHDefault, is set R8 68K IPRETH resistor. Used to set programmable pre-charge current threshold above the default one. If not mounted, the IPRETHDefault, is set R9 470R If a NTC is not used, a half value of R3 must be mounted to keep the TH voltage in the correct window R10 N.M It has the same function of R6. Moreover, if it is replaced with a short-circuit, when J5 is closed, the timer is reset (falling edge) C1 1µF Input capacitor C2 10nF TMAX capacitor. Used to set the maximum charging time C3 1µF Output capacitor C4 1µF VREF filter capacitor. Not mounted LD1 GREEN ST1 LED EVAL6924D Revision history Figure 2. Package - VFQFPN16 ) s ( t c u d o ) r s ( P t c e t u e d l o o r s P b e O t e l ) o s ( s t b c u O d o ) r s P ( t c e t u e l d o o r s P b O e t e l o s b O 2 Revision history Table 2. Revision history Date Revision 21-Nov-2006 1 Changes First issue 3/4 EVAL6924D ) s ( t c u d o ) r s ( P t c e t u e d l o o r s P b e O t e l ) o s ( s t b c u O d o ) r s P ( t c e t u e l d o o r s P b O e t e l o s b O Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. 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