AQ120 Battery Charger Controller SOT23-5 and SC70-5 Package Preliminary Specification Revision 1.8 General Description The AQ120 is a low cost linear battery charger controller with similar features to the industry standard “1734” style controller, but with the extra ability to charge multiple cell Lithium Ion batteries as well as NiCad types. In addition, the maximum Vin is 18 volts. The AQ120 flexibility allows the setting of the charge voltage and current with a minimum number of external components. The open collector output is capable of driving an external PNP transistor. A temperature stable bandgap reference (1.25 V) controls the maximum output voltage, while a current control circuit sets a constant charging current. Block Diagram www.acutechnology.com April 1, 2006 Applications • Battery chargers Features • 1.25V reference with 1% accuracy • Multiple cell compatible • Programmable charge current • Low current consumption • Offered in ultra small SC70-5 package • No blocking diode required • Wide Vin range: 2.5V to 18V • 25mA drive current sink • No battery drain in shutdown • Sleep mode with input supply removal • RoHS compliant available Pin Configuration AQ120 AQ120 Acutechnology Semiconductor Inc. Typical Application Note: The values of R1and R2 set the charge voltage (up to three Li-Ion cells is possible). The value of R3 sets the charge current. Pin Descriptions Pin Pin Name Function 1 DRIVE 2 GND 3 IPROG 4 VCC Positive supply 5 VREF Voltage programming pin; has a threshold of 1.25V. Output of error amplifier. 25 mA sink capability Ground Current programming pin, has a threshold of 200 mV. Ordering Information Device Operating Tj %Tol Pkg Type VOUT Wrap Order Number AQ120 -20C˚ ≤ 105C˚ 1.0 SOT-23-5 1.25V T&R AQ120DY-M5-AJ-TR AQ120 -20C˚ ≤ 105C˚ 1.0 SOT-23-5 1.25V T&R AQ120DY-M5-AJ-TRL AQ120 -20C˚ ≤ 105C˚ 1.0 SC70-5 1.25V T&R AQ120DY-C5-AJ-TR AQ120 -20C˚ ≤ 105C˚ 1.0 SC70-5 1.25V T&R AQ120DY-C5-AJ-TRL Note: The TRL parts are Lead Free and RoHS compliant. www.acutechnology.com 2 Rev. 1.8 April 1, 2006 AQ120 Acutechnology Semiconductor Inc. Absolute Maximum Ratings Parameter Value Units VCC Voltage 18 V DRIVE Voltage 18 V REF Voltage 18 V VCC, DRIVE, REF Current 50 mA Operating Junction Temperature 150 ºC Lead Temperature (soldering 10 seconds) 300 ºC -80 to +150 ºC Storage Temperature Range Electrical Specifications Electrical characteristics are guaranteed over the full temperature range –20ºC <Tj< 105ºC. Ambient temperature must be de-rated based upon power dissipation and package thermal characteristics. Unless otherwise stated, test conditions are VCC = 5V, VDRIVE = 4.3V, VIPROG = 0V. Symbol Parameter Conditions Vcc Supply Voltage Range Icc Vcc Quiescent Supply Current VREF= VCC= VDRIVE= 5V Reference Voltage Ta=25ºC VREF Min Typ Max Units 2.5 5 18 V 150 300 µA 1.250 1.263 V 1.238 Reference Temperature Deviation Reference variation with Supply Voltage -20ºC <Tj<105ºC 0.5 1 % VCC=2.5V to 18V IDRIVE = 500 µA 0.3 0.6 mV/V Reference input current VREF = 0V Output Saturation Voltage IDRIVE = 10 mA, VREF = 0V I DRIVE Drive Current V DRIVE = 5V, VREF = VIPROG = GND I LEAK Output Leakage Current VDRIVE = VREF = VCC = 18V VIPROG IPROG threshold voltage Gain Delta Vref / VIPROG IIPROG I PROG input current TC REF LnREG I REF VDRVlow www.acutechnology.com -50 Tj=25ºC -20<Tj<105ºC T=25ºC -20<Tj<105ºC VIPROG = 0V VIPROG = -250 mV 3 -20 1.8 20 190 195 36 nA 2.2 25 V mA 200 400 nA 200 200 40 40 210 205 mV -50 -160 Rev. 1.8 44 mV/ mV µA April 1, 2006 AQ120 Acutechnology Semiconductor Inc. Typical Performance Characteristics 900 Cons tant c urrent mode 800 700 600 500 400 300 Cons tant v oltage mode 200 100 2 2.2 2.4 2.6 V 2/V 2.8 3 3.2 3.4 Charge c urrent v s battery v oltage 3.6 3.8 4 4.2 200mV /div 1 c ell Lithium Ion battery Fig.1 Charge current vs battery voltage 4 Constant voltage 3.5 3 2.5 2 1.5 1 900 Constant current 700 500 300 100 0 1 2 3 4 Fig. 2 Battery charge vs time www.acutechnology.com 4 Rev. 1.8 April 1, 2006 AQ120 Acutechnology Semiconductor Inc. Operation The AQ120 is a linear battery charger controller. Charging begins when Vcc rises above 2.5V. When charging, the collector of the external PNP transistor provides the charge current. Below the target charge voltage the controller is in current mode. When the battery voltage reaches the target voltage then the controller switches to the voltage mode. The target voltage is programmable through an external resistor divider. This allows flexibility to set the voltage (to one or more cells Li ion batteries, NiMH or NiCd batteries). In current mode the AQ120 regulates the voltage across the sense resistor to be 200 mV. The charge current is therefore given by Ich = 0.2V / Rsense. An additional resistor is recommended (as in the typical application diagram) for stability reasons, then the threshold is actually increased by the value of the resistor multiplied by the current out of the IPROG pin. The AQ120 is designed for a maximum current in excess of 1A. The external PNP transistor must have adequate beta, low saturation voltage and sufficient power dissipation capability. With low supply voltages, the PNP saturation voltage becomes important as well. In constant voltage mode, the controller will control the battery voltage not to exceed the target charge voltage. When Vcc is applied, the charger can be manually shut down by opening the resistor R2 of the resistor divider (floating the otherwise grounded end of R2) or by pulling high the REF pin. This can be used in conjunction with an external thermostat switch. When input power is removed or manual shutdown is entered, the charger will drain only very small leakage currents from the battery, thus maximizing battery standby time. The leakage current is due to the reverse-biased base-emitter junction of the external PNP transistor. A LED indicator can be added to show when the charger is operational, simply connecting the base-emitter of an additional PNP transistor in parallel to the base-emitter of Q1 and its collector to the LED. The AQ120 contains two control loops. To maintain good AC stability in the constant voltage mode, a capacitor of at least 10uF in series to a 3.3 ohms resistor is usually required from the collector of the external PNP to ground. The stability of the system is also depending on the type of external PNP transistor. High beta PNPs may be reducing the phase margin in some cases. R6 and C3 insure system stability in current mode without affecting the voltage mode. The use of the resistor R6 affects the threshold. For example for R6=150 ohms the threshold moves from 200 mV to 215 mV. Furthermore the use of an external PMOS in place of the PNP represents a valid alternative to the application when wanting to minimize the current consumption during charge. www.acutechnology.com 5 Rev. 1.8 April 1, 2006 AQ120 Acutechnology Semiconductor Inc. Package Dimensions SOT23-3, SOT23-4, SOT23-5, SOT23-6 www.acutechnology.com 6 Rev. 1.8 April 1, 2006 AQ120 Acutechnology Semiconductor Inc. SC70-3, SC70-4, SC70-5, SC70-6 Contact Information Acutechnology Semiconductor Inc. 3487 McKee Rd. Suite 52 San Jose CA , USA 95127 TEL: FAX: website: (408) 259-2300 (408) 259-9160 www.acutechnology.com Disclaimer The information furnished by Acutechnology in this data sheet is believed to be accurate and reliable. However, Acutechnology assumes no responsibility for its use. Acutechnology reserves the right to change circuitry and specifications at any time without notification to the customer. Life Support Policy Acutechnology Products are not designed or authorized for use as components in life support devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. www.acutechnology.com 7 Rev. 1.8 April 1, 2006