ACT2802 Rev 0, 21-Jan-14 5V/2.5A Backup Battery Pack Manager FEATURES Dedicated Single Chip Solution for Mobile APPLICATIONS Power With Minimal Component Count 5V/2.5A Constant Output Current Limit in Boost Mode 2.5A Switching Charger Current Limit Programmable 4.1V to 4.35V Battery Voltage 95% Boost Efficiency (Vbat=4.1V) Adaptive to 10mA-2400mA Input Sources Battery Disconnection at Output Short <10µA Low Battery Leakage Current at HZ Backup Battery Pack Power Bank Mobile Power Standalone Battery Charger with USB Output GENERAL DESCRIPTION ACT2802 is a space-saving and high-performance low-profile single-chip solution for backup battery pack and standalone battery charger. ACT2802 integrates all the functions that a backup battery pack needs, including switching charger, boost converter and LED indication. Mode During Storage Boost Auto Turn-off at No Load and Push Button Turn-on Battery Over Current, Over Voltage, Over Temperature and Short Circuit Protections Boost Auto Startup with Load Detection Up to 3.0A Input Current Limit with Prioritized Power Path to Output 5V+/-100mV Output Voltage in Boost Mode 1.1MHz/0.55MHz Switching Frequencies 2.2uH Inductor and Low Profile Ceramic Capacitors 4 LEDs Battery Level and Status Indication Battery Impedance Compensation Full Cycle of Battery Charge Management Preconditioning, Fast Charge, Top off and End of Charge Charge Current Foldback at 110°C Die Temperature IC Over Temperature Protection at 160°C QFN4x4-24 Package ACT2802 operates at 1.1MHz for switching charger and 0.55MHz for boost converter allowing tiny external inductor and capacitors. ACT2802 provides a direct power path from input to output with programmable current limit while providing power to switching charger. Output has higher priority than battery charger if the programmed input current limit is reached. ACT2802 charges battery with full cycle of preconditioning, fast charge with constant current and constant voltage until end of charge. The battery charger is thermally regulated at 110°C with charge current foldback. ACT2802 boost converter steps battery voltage up to 5V. Boost converter features high efficiency, constant current regulation, short circuit protection and over voltage protection. ACT2802 provides 3.5mA constant currents to drive 4 LEDs to indicate battery level and charge status. Boost Output Voltage (V) Boost CC/CV Profile 5.5 VBAT =3.2V 5.0 VBAT =3.7V 4.5 4.0 VBAT =4.1V 3.5 3.0 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 Output Current (A) Innovative PowerTM -1- www.active-semi.com Copyright © 2014 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 ORDERING INFORMATION PART NUMBER BOOST SWITCH FREQUENCY OUTPUT CHARGE CURRENT PACKAGE PACKING ACT2802QL-T 0.55MHz 5V/2.5A 2.5A QFN44-24 TAPE & REEL, 3KU/REEL PIN CONFIGURATION TOP VIEW 24 23 22 21 20 19 HZ PB 1 18 2 17 AGND nPG ILIM VIN 3 16 4 15 5 14 EP 6 7 8 9 10 13 11 LED1 BTV ICST IOST CSN CSP 12 QFN44-24 Innovative PowerTM -2- Active-Semi Confidential―Do Not Copy or Distribute ActiveSwitcherTM is a trademark of Active-Semi. www.active-semi.com Copyright © 2013 Active-Semi, Inc. ACT2802 Rev 0, 21-Jan-14 PIN DESCRIPTIONS PIN NAME DESCRIPTION 1 HZ Boost/high-Z mode enable pin, internally pulled up by a 3MΩ resistor to battery. When HZ pin is pulled ground, boost is enabled if VIN is not present. 2 PB Push button input, connect a push button from this pin to AGND, internally pulled up by a 3MΩ resistor to battery. When this pin is pushed for 100ms, LED1-4 indicators are enable for 5 seconds. PB starts up boost converter if HZ pin is grounded and VIN is not present. 3 AGND 4 nPG Drive external P-FET to protect output short circuit and leakage during shutdown. nPG pin is pulled up to VOUT internally. nPG pin is pulled low if VOUT is in the range. 5 ILIM Input current limit setting pin. Connect a resistor from this pin to AGND to set the input current limit. The current setting ranges from 1.0A-3.0A. 6 VIN USB or AC adaptor input. When VIN is valid, charge and power path is enabled. 7, 8 VOUT 9, 10 SW 11 PGND Power ground. PGND is connected to the source of low-side N-channel MOSFET and the MOSFET’s gate driver. 12 BAT Battery input. Connected to the battery pack positive terminal to provide power in High -Z mode. Bypass to PGND with a high quality ceramic capacitor placed as close to the IC as possible. 13 CSP Positive terminal of charge current sense input. Kevin sense is required with 10nF ceramic capacitor right across CSP and CSN pins. 14 CSN Negative terminal of charge current sense input. 15 IOST Output current setting. Connect a resistor from this pin to AGND to set output constant current. The current setting ranges from 1.0A-2.5A. 16 ICST Fast charge current setting pin. Connect a resistor from this pin to AGND to set the charge current. The current setting ranges from 1.0A-2.5A. 17 BTV Battery termination voltage setting. Connect a resistor from this pin to AGND to program battery charge termination voltage. 18 LED1 Battery level indicator. An internal 3.5mA sink current limit is built in. 19 LED2 Battery level indicator. An internal 3.5mA sink current limit is built in. 20 LED3 Battery level indicator. An internal 3.5mA sink current limit is built in. 21 LED4 Battery level indicator. An internal 3.5mA sink current limit is built in. 22 RIMC Battery impendence compensation input. Connect to a resistor from this pin to APNG to program the battery impedance. 23 BLVS Battery level voltage shift. Connect a resistor from this pin to AGND to shift the battery LED indication thresholds. 24 TH Temperature sensing input. Connect to battery thermistor terminal. If no use, put 10K pulled down resistor. 25 EP Exposed pad. Must be soldered to ground on the PCB. Logic Ground. Output pin. Bypass to PGND with a high quality low ESR and ESL ceramic capacitor placed as close to the IC as possible. Internal switch to output inductor terminal. Innovative PowerTM -3- Active-Semi Confidential―Do Not Copy or Distribute ActiveSwitcherTM is a trademark of Active-Semi. www.active-semi.com Copyright © 2013 Active-Semi, Inc. ACT2802 Rev 0, 21-Jan-14 ABSOLUTE MAXIMUM RATINGS PARAMETER VALUE UNIT -0.3 to 6.5 V Junction to Ambient Thermal Resistance 40 °C/W Maximum Power Dissipation 2.5 W Operating Ambient Temperature -40 to 85 °C Operating Junction Temperature -40 to 150 °C Storage Junction Temperature -40 to 150 °C 300 °C All the Pin to PGND and AGND Lead Temperature (Soldering 10 sec.) : Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability. Innovative PowerTM -4- Active-Semi Confidential―Do Not Copy or Distribute ActiveSwitcherTM is a trademark of Active-Semi. www.active-semi.com Copyright © 2013 Active-Semi, Inc. ACT2802 Rev 0, 21-Jan-14 ELECTRICAL CHARACTERISTICS (VIN = 5V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Input Current Limit Input Voltage Range 4.5 VIN Over Voltage Protection VIN rising, VIN_OVP Input Voltage Validation Time VIN_UVLO<VIN<VIN_OVP Input Current Limit Setting Range RILIM=0.806kΩ—2.4kΩ Input Current Limit RILIM=0.806kΩ 5.5 6.0 5.5 V 6.5 V 32 1.0 ms 3.0 3.0 Input Current Limit Gain A A 2000 Leakage Current from VOUT to VIN in Boost Mode 3.0V<VBAT<4.35V, Ta=25℃ 0 10 µA Battery Discharge Current in High-Z Mode 3.0V<VBAT<4.35V, Ta=25℃ 7.5 15 µA Power Switches VIN-to-VOUT FET on Resistance 80 mΩ VOUT-to-SW FET on Resistance 60 mΩ SW-to-PGND FET on Resistance 65 mΩ Buck Converter Switching Frequency ACT2802QL-T High Side Switch Peak Current Limit -15% 1.1 4.5 6 A 100 ns Minimum On-time +15% MHz Over Temperature Protection (OTP) OTP rising 160 ℃ OTP Hysteresis OTP falling 35 ℃ Charge Mode Charge Current Setting Range Rcs=25mΩ, RICST=20kΩ—50kΩ Charge Current Setting (ICHRG) Rcs=25mΩ, RICST=43.2kΩ 1.0 Thermal Regulation Temperature Battery Adjust Voltage(VBAJ) Rbtv=25kΩ End of Charge (EOC) Voltage -0.5% 2.5 A 2.1 A 110 ℃ 0.1 V 4.1+VBAJ 0.5% V EOC Voltage Accuracy Rbtv=0 4.1 V Battery Over Voltage Threshold VBAT rising 4.6 V Battery Over Voltage Threshold Hysteresis VBAT falling 200 mV Fast Charge Current VBAT=3.5V ICHRG A Precondition Charge Current 2.4V≤VBAT≤2.8V, Percent of ICHRG 10 % Innovative PowerTM -5- Active-Semi Confidential―Do Not Copy or Distribute ActiveSwitcherTM is a trademark of Active-Semi. www.active-semi.com Copyright © 2013 Active-Semi, Inc. ACT2802 Rev 0, 21-Jan-14 ELECTRICAL CHARACTERISTICS (VIN = 5V, TA = 25°C, unless otherwise specified.) PARAMETER Precondition Voltage Threshold TEST CONDITIONS MIN VBAT rising, Rbtv=0 Precondition Voltage Threshold Hysteresis TYP MAX UNIT 2.8 V 130 mV Low VBAT Charge Current VBAT=1V, RICST=43.2kΩ 200 mA EOC Current Threshold VBAT=4.2V, percent of the fast charge current 13 % 200 mV Charge Restart Voltage Threshold TH Upper Temperature Voltage Threshold Cold detect NTC thermistor 1.45 1.5 1.55 V TH Lower Temperature Voltage Threshold Hot detect NTC thermistor 0.28 0.3 0.32 V TH Hysteresis 50 mV TH Internal Pull-up Current 60 µA Charge Current Foldback Charge Current Reduction Threshold1 of Vout1 Starting foldback point Charge Current Reduction Threshold2 of Vout1 Stop foldback point, RCS=25mΩ, RICST=43.2kΩ 4.63 4.7 4.77 4.57 V V Boost Mode Input Voltage Operation Range 3.0 -15% 0.55 4.5 V +15% MHz Switching Frequency ACT2802QL-T Input Voltage UVLO VBAT rising 3.3 V Input Voltage UVLO Hysteresis VBAT falling 400 mV Output Voltage Ta=25℃ Output Voltage Accuracy All conditions 4.97 5.05 5.10 V -3 VOUT 2 % 80mA-1A-80mA, 0.1A/us 4.75 5.25 V 1A-2.0A-1A, 0.1A/us 4.7 5.25 V Output Voltage Transient Response Output Over Voltage Protection VOUT rising 5.7 V Output Over Voltage Protection Hysteresis VOUT falling 300 mV Output Current Regulation Range Rcs=25mΩ, RIOST=37.4kΩ—93.7kΩ Output Current Limit Rcs=25mΩ, RIOST=91kΩ 1.0 Minimum On-Time Low Side Switch Peak Current Limit VBAT=3.6V, VOUT=5V Soft-Startup Time Innovative PowerTM -6- Active-Semi Confidential―Do Not Copy or Distribute ActiveSwitcherTM is a trademark of Active-Semi. 4.9 2.5 A 2.4 A 100 ns 6.9 A 400 µs www.active-semi.com Copyright © 2013 Active-Semi, Inc. ACT2802 Rev 0, 21-Jan-14 ELECTRICAL CHARACTERISTICS (VIN = 5V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Under Voltage Protection (UVP Threshold) VOUT falling 4.25 V Under Voltage Protection (UVP Threshold) VOUT rising 4.6 V 3 ms UVP Blanking Time During Startup UVP Sense Detection Time VOUT falling 20 µs Restart After UVP Hiccup mode 2 s Light Load Current Shut off Threshold 40 mA Light Load Current Detect Time 90 s HZ Pin High Voltage HZ voltage rising HZ Pin Low Voltage HZ voltage falling 0.9 0.4 1.4 V 0.75 V HZ Internal Pull-up Resistor 3 MΩ PB Turn off Boost Time 3 s PB Turn on Boost Time 100 ms 2 s Mode Transition Transition Waiting Time between Charge Mode and Boost Mode TRANTIME Battery Level Indication Battery Impedance Compensation Range Battery Impedance Compensation 40 Rcs=25mΩ, RIMC=200kΩ PB Deglitch Time PB High Input Voltage PB voltage rising PB Low Input Voltage PB voltage falling PB Internal Pull-up Resistor LED Indication Time PB is pushed and released LED Flash Frequency Charging, LED flash 1s on and 1s off Innovative PowerTM -7- Active-Semi Confidential―Do Not Copy or Distribute ActiveSwitcherTM is a trademark of Active-Semi. 500 200 mΩ 100 ms 0.9 0.4 mΩ 1.4 V 0.75 V 3 MΩ 5 s 0.5 Hz www.active-semi.com Copyright © 2013 Active-Semi, Inc. ACT2802 Rev 0, 21-Jan-14 FUNCTIONAL BLOCK DIAGRAM FUNCTIONAL DESCRIPTION at VOUT, and the current limit switch Q1 is turned off, and the reverse current from VOUT to VIN is blocked. In HZ mode, all the switches are turned off and the drainage current from battery is very low. The system operation flow chart as shown in Figure 1. ACT2802 is a complete battery charging and discharging power management solution for applications of single-cell lithium-based backup battery pack or power bank. There is a power path from input to output with programmable input current limit. When output is over loaded, the input switch Q1 starts going into linear mode and thus output voltage starts to drop. If output voltage drops below 4.25V, the input switch Q1 turns off and restart in 2 seconds. Any transitions between boost mode and charge mode go through HZ mode by turning off all the switches Q1-Q3 into HZ mode for 2 seconds before enabling the other mode. With the advanced ACT2802 architecture, a synchronous buck/boost converter is connected from VOUT to switching node (SW). With the bidirectional architecture, the converter could be configured as either buck to charge battery or boost to discharge battery. With switching charger and discharger, the higher charge current and higher conversion efficiency are achieved. The modes are determined by HZ pin and VIN pin as shown in the table 1. A valid VIN voltage forces ACT2802 into charge mode. Boost mode is enabled if HZ pin is pulled low and VIN is invalid or not present. When HZ=0, if PB is pulled low for more than 100ms, boost converter is enabled. A running boost is disabled if one of the following conditions is met: Modes of Operation 1. After PB is released, if PB is pulled low for more than 3 seconds. ACT2802 has 3 operation modes: charge mode, boost mode and high-impedance (HZ) mode. In charge mode, the input current limit is enabled and the Q2 and Q3 operate as a buck converter to charge battery. In boost mode, Q2 and Q3 operate as boost converter to step battery voltage up to +5V Innovative PowerTM 2. Boost converter output current is below light load threshold for 1.5 minutes. 3. Battery voltage falls below the boost cut-off threshold. -8- Active-Semi Confidential―Do Not Copy or Distribute ActiveSwitcherTM is a trademark of Active-Semi. www.active-semi.com Copyright © 2013 Active-Semi, Inc. ACT2802 Rev 0, 21-Jan-14 FUNCTIONAL DESCRIPTION Figure 1: ACT2802 System Operation Flow Chart to decrease as necessary to maintain charging at the termination voltage. Table 1: Mode Selection HZ PIN 0 0 1 1 VIN Valid 0 1 0 1 Mode Boost Charge HZ Charge Precondition Charge A new charging cycle begins with the precondition state, and operation continues in this state until VBAT exceeds the precondition threshold voltage. When operating in precondition state, the cell is charged at a reduced current, 10% of the programmed maximum fast charge constant current. Once VBAT reaches the precondition threshold voltage the state machine jumps to the fast charge state. Input Current Limit When the input current reaches the programmed value, switch Q1 goes into linear mode and output voltage starts to drop. When output voltage drops to 4.25V, hiccup mode is triggered and switch Q1 turns off and restart in 2 seconds. Fast Charge Switching Battery Charger If battery voltage is above preconditioning threshold, buck converter charges battery with constant current. In fast charge state, the ACT2802 charges at the current set by the external resistor connected at the ICST pin. During a normal charge cycle fast charge continues in CC mode until VBAT reaches the charge termination voltage, at which point the ACT2802 charges in top off state. ACT2802 is configured in charge mode (buck mode) when VIN is valid. In this mode, a battery is charged with preconditioning, fast charge, top-off and end of charge (EOC). The typical charge management is shown in Figure 2 and Figure 3. CC/CV Regulation Loop There are CC/CV regulation loops built in ACT2802, which regulates either current or voltage as necessary to ensure fast and safe charging of the battery. In a normal charge cycle, this loop regulates the current to the value set by the external resistor at the ICST pin. Charging continues at this current until the battery cell voltage reaches the termination voltage. At this point the CV loop takes over, and charge current is allowed Innovative PowerTM Top Off With the battery voltage approaches the EOC voltage set by the BTV pin. Charge current decreases as charging continues. In the top off state, the cell is charged in constant voltage (CV) mode. During a normal charging cycle charging proceeds until the charge current decreases below -9- Active-Semi Confidential―Do Not Copy or Distribute ActiveSwitcherTM is a trademark of Active-Semi. www.active-semi.com Copyright © 2013 Active-Semi, Inc. ACT2802 Rev 0, 21-Jan-14 FUNCTIONAL DESCRIPTION the end of charge (EOC) threshold, defined as 13% of fast charge current. When this happens, the state machine terminates the charge cycle and jumps to the EOC state. charge mode and keep monitoring the battery voltage. End of Charge When battery voltage drops by 200mV below the end of charge voltage, the charger is reinitiated with constant current charge. When charges current decreases to 13% of set fast charge current, the buck converter goes into end of Recharge Figure 2. Typical Li+ Charge Profile and ACT2802 Charge States A: PRECONDITION STATE B: FAST-CHARGE STATE C: TOP-OFF STATE D: END-OF-CHARGE STATE Figure 3. Charger State Diagram Innovative PowerTM - 10 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 programmed by a resistor connected from BLVS pin to AGND as shown in Figure 5. The following equation shows the LED4 voltage threshold: APPLICATIONS INFORMATION Battery Charge Termination Voltage Battery charge termination voltage is set by a resistor Rbtv connected from BTV pin to AGND as shown in Figure 4. The battery charge termination voltage is estimated as the following equation: V BAT (V ) 4 .1(V ) Rbtv 4 10 6 (V ) VBATLED4 (V ) 3.5(V ) 0.01(mA) RBLVS (k) (2) (1) Rbtv is selected based on the battery voltage rating. 1% accuracy resistor is recommended for Rbtv. Figure 5. Battery level voltage shift setting circuit As long as LED4 is set, all the other 3 LED thresholds is fixed as shown in the table 3: Table 3: 4 LED Voltage Thresholds RBLVS (ohm) 50K 60K 70K 80K LED1 3.35V 3.45V 3.55V 3.65V LED2 3.60V 3.70V 3.80V 3.90V LED Status Indication LED3 3.75V 3.85V 3.95V 4.05V 4 LEDs ON/OFF and flash show the charge status and the remained capacity level as shown in the table 2. The LED status is based on battery voltage and operation modes. In charge mode, when a battery is fully charged, flashing stops and all the 4 LEDs are solid on. LED4 4.00V 4.10V 4.20V 4.30V Figure 4. Battery terminal voltage setting circuit Battery level voltage shift (BLVS pin) LED1-4 voltage thresholds are adjusted from HZ mode during charging and discharging based on the compensated impedance. Those thresholds are Input Current Limit An external resistor is used to set the input current limit connected from ILIM pin to AGND as shown in Figure 6. Input current limit has built-in soft startup and current foldback control loop. The input current limit is estimated as the following equation: I ILIM (A) 2 .4 (V) R ILIM (k ) (3) Table2: LED Indication Charge Mode PB time>100ms (Boost or HZ Mode) LED1 LED2 LED3 LED4 LED1 LED2 LED3 LED4 VBAT<LED1 Flash Off Off Off Off Off Off Off LED1≤VBAT<LED2 On Flash Off Off On Off Off Off LED2≤VBAT<LED3 On On Flash Off On On Off Off LED3≤VBAT<LED4 On On On Flash On On On Off VBAT≥LED4 On On On Flash On On On On VBAT≥LED4 (End of Charge) On On On On On On On On Innovative PowerTM - 11 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 from IOST pin to AGND as shown in Figure 10. The boost output current is estimated as the following equation: I IOST (A) Figure 6. 2 R (k ) ( A ) IOST 3 Rc s (m ) (5) Input current limit setting circuit Input current limit at various resistor curve is shown in Figure 7. 3.5 Figure 10. 3.0 IILIM (A) 2.5 Boost output current setting circuit Figure 11 gives out boost output current with various RIOST. 2.0 1.5 3.0 1.0 0.5 0.6 1.0 1.4 1.8 2.2 2.6 2.5 3.0 2.0 Figure 7. IOUT (A) RILIM (kΩ) Input current limit setting Battery Fast Charge Current 1.0 0.5 Battery fast charge current is set by a resistor connected from ICST pin to AGND as shown in Figure 8. Figure 9 gives out different fast charge current with various RICST. The battery fast charge current is estimated as the following equation: Ic ( A ) 1 .25 ( A ) 1.5 0 0 20 40 60 80 100 RIOST (kΩ) Figure 11. Boost output current setting Battery Impedance Compensation R ICST ( k ) Rcs ( m ) (4) An external resistor is used to set the impedance from 40mΩ to 500mΩ as shown in Figure 12. RIMC is corresponding to battery impedance. Higher RIMC gives higher compensation voltage which is positively proportional to battery charge/discharge current. Select RIMC based on battery impedance: Figure 8. R IMC (k ) Battery fast charge current setting circuit 25 R (m ) R cs (m ) (6) VBAT (V ) BAT(V ) I BAT ( A) R(m) 10-3 3.0 (7) ICHRG (A) 2.5 2.0 1.5 1.0 0.5 0 0 10 20 30 40 50 60 RICST (kΩ) Figure 9. Figure 12. Battery fast charge current setting Boost Output Constant Current Boost output current is set by a resistor connected Innovative PowerTM Battery impedance compensation setting circuit The battery impedance as shown in the table 4 according to the RIMC and Rcs: - 12 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 Table 4: Battery Impedance RIMC(KΩ) Battery Impedance R(mΩ) Flashlight Circuit 50 100 200 Rcs=25mΩ 50 100 200 Rcs=50mΩ 100 200 400 Figure 16 shows a circuit with flashlight driver and control. Boost Output Plug-in Auto Detection Figure 13 provides a solution for auto plug-in detection. Figure 16. Flashlight circuit LEDs on in Boost Mode LEDs can be always on during boost mode, the schematic is shown in Figure17. Figure 13. Boost output auto detection circuit Input Over Voltage Surge In the case of pure ceramic input capacitor is chosen, if the input cable is long, stray inductance may cause over voltage spikes as twice as the steady-state voltage when input source is plugged in. Below input circuit is recommended to avoid input voltage surge. R1 resistor is added in series with capacitor C1 to damp the potential LC resonance as shown in Figure 14. Figure 17. LEDs on in boost mode circuit Inductor and Capacitor Selection ACT2802 supports SMD components. 2.2uH inductor is recommended. Input side, 4.7uF ceramic capacitor in series with 2.7Ω resistor are recommended, on battery side, 22uF ceramic capacitors is recommended while on output side, 22uFx2 ceramic capacitors are recommended. Figure 14. Battery Temperature Monitoring Input over voltage surge protection circuit External Input Over Voltage Protection Considering the maximum voltage rating at VIN pin, the external OVP circuit as shown in Figure 15 is recommended if input voltage may go higher than 7V. With the enhanced OVP circuit, input voltage can be up to 18V. Figure 15. In a typical application, the TH pin is connected to the battery pack's thermistor input as shown in Figure 18. The ACT2802 injects a 60µA current out of the TH pin into the thermistor, so that the thermistor resistance is monitored by comparing the voltage at TH to the internal VTHL and VTHH thresholds of 0.3V and 1.5V, respectively. When VTH > VTHH or VTH < VTHL charging and the charge timers are suspended. When VTH returns to the normal range, charging and the charge timers resume. The net resistance from TH to GND required to cross Input over voltage protection Innovative PowerTM The ACT2802 continuously monitors the temperature of the battery pack by sensing the resistance of its thermistor, and suspends charging if the temperature of the battery pack exceeds the safety limits. - 13 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 the threshold is given by: 60µA×RNOM×kHOT=0.3V→ RNOM×kHOT=5kΩ 60µA×RNOM×kCOLD=1.5V → RNOM×kCOLD= 25kΩ where RNOM is the nominal thermistor resistance at room temperature, and kHOT and kCOLD are the ratios of the thermistor's resistance at the desired hot and cold thresholds, respectively. Figure 18. Battery thermal circuit Innovative PowerTM - 14 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 PC Board Layout Guidance When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the IC. 1. Arrange the power components to reduce the AC loop size, VIN pin, Vout pin, SW pin and the schottky diode. 2. Place input decoupling ceramic capacitor C3 and R10 as close to VIN pin as possible. Resistor R10 is added in series with capacitor C3 to damp the potential LC resonance . 3. Use copper plane for power GND for best heat dissipation and noise immunity. 4. Place CSP and CSN capacitor C6 (10nF) close to CSP and CSN pin as possible, use Kevin Sense from sense resistor R2 and R2A to CSP and CSN pins. 22uF decoupling capacitor is added close to BAT pin. 5. Place the ceramic capacitor C2 and D1 as close to VOUT and PGND as possible, SW goes under the C2 (recommend C2 to use 1206 size). SW pad is a noisy node switching. It should be isolated away from the rest of circuit for good EMI and low noise operation. 6. Thermal pad is connected to GND layer through vias (recommend 4X4 pins and the aperture is 10mil). Ground plane, PGND and AGND is single point connected under the ACT2802 thermal pad through vias to limited SW area. 7. From BAT pin to the Battery positive terminal, need to lay the divided line to ensure the battery voltage accuracy of sampling. 8. RC snubber is recommended to add across SW to PGND to reduce EMI noise. 1A /20V schottky is added to across VOUT and SW pins. A demo board PCB layout example is shown in the figure 19. Figure 19. PCB Layout Bottom Layer Top Layer Innovative PowerTM - 15 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 BLVS RIMC LED4 LED3 LED2 VOUT SW SW PGND BAT TH VOUT LED1 LED2 LED3 LED4 R8 R7 R6 Figure 20 Typical application circuit (Input current limit 3.0A, fast charge current limit 2.1A, boost output constant current limit 2.4A) Innovative PowerTM - 16 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 BOM List ITEM REFERENCE DESCRIPTION QTY MANUFACTURER 1 L1 Core 6.5*3*3 Dip 2.2uH 6A 1 Sunlord 2 Q1 AO4503, Rdson=19mΩ at VGS = - 4.5 V 1 Vishay 3 Q3 MMBT3906 1 Vishay 4 D1 SS12, Vf=0.5V, 20V Schottky 1 Panjit 5 D2 1N4148, Vf=0.7V, 75V Schottky 1 Vishay 6 C2,C5,C9 Ceramic capacitor, 22uF/10V, X7R, 1206 3 Murata/TDK 7 C3 Ceramic capacitor, 4.7uF/10V, X7R, 1206 1 Murata/TDK 8 C4 Ceramic capacitor, 0.1uF/10V, X7R, 0603 1 Murata/TDK 9 C6 Ceramic capacitor, 10nF/10V, X7R, 0603 1 Murata/TDK 10 C7 Ceramic capacitor, 2.2nF/10V, X7R, 0603 1 Murata/TDK 11 C8,C11,C12,C13 Ceramic capacitor, 2.2uF/10V, X7R, 0603 4 Murata/TDK 12 R1 Chip Resistor, 806Ω, 1/10W, 1%, 0603 1 Murata/TDK 13 R2,R2A Chip Resistor, 50mΩ, 1/4W, 1%, 1206 2 Murata/TDK 14 R3 Chip Resistor, 93.1kΩ, 1/10W, 1%, 0603 1 Murata/TDK 15 R4,R17 Chip Resistor, 43.2kΩ, 1/10W, 1%, 0603 2 Murata/TDK 16 R5 Chip Resistor, 25kΩ, 1/10W, 1%, 0603 1 Murata/TDK 17 R6 Chip Resistor, 10kΩ, 1/10W, 5%, 0603 1 Murata/TDK 18 R7 Chip Resistor, 60kΩ, 1/10W, 1%, 0603 1 Murata/TDK 19 R8 Chip Resistor, 100kΩ, 1/10W, 1%, 0603 1 Murata/TDK 20 R9 Chip Resistor, 1Ω, 1/8W, 5%, 0805 1 Murata/TDK 21 R10 Chip Resistor, 2.7Ω, 1/4W, 5%, 1206 1 Murata/TDK 22 R11 Chip Resistor, 200kΩ, 1/10W, 5%, 0603 1 Murata/TDK 23 R12,R13 Chip Resistor, 715kΩ, 1/10W, 5%, 0603 2 Murata/TDK 24 R14,R16 Chip Resistor, 49.9kΩ, 1/10W, 5%, 0603 2 Murata/TDK 25 R15 Chip Resistor, 75kΩ, 1/10W, 1%, 0603 1 Murata/TDK 26 R18,R19 Chip Resistor, 100kΩ, 1/10W, 5%, 0603 2 Murata/TDK 27 R20 Chip Resistor, 2.2Ω, 1/10W, 5%, 0603 1 Murata/TDK 28 LED1,LED2, LED3,LED4 LED, 0603, Blue 4 LED Manu 29 PB Push Button Switch 1 Nikkai Omron 30 USB 10.2*14.6*7mm, 4P 1 31 Micro-USB MICRO USB 5P/F SMTB 1 32 U1 IC, ACT2802, T-QFN 44-24 1 Innovative PowerTM ACT - 17 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Schematic as show in Figure 20, Ta = 25°C, unless otherwise specified) Battery Charge V/I Profile Charge Current VS. Output Current 2500 Input Current (mA) 2500 2000 Input Current 1500 Charge Current 1000 500 VIN = 5.0V ICHRG = 2.1A ACT2802-02 ACT2802-01 VIN = 5.0V VBAT = 3.5V Charge Current (mA) 3000 2000 1500 1000 500 0 0 0 500 1000 1500 2000 2500 0 0.5 1.0 1.5 2.0 Output Current (mA) 4.0 4.5 2100 2400 Boost Efficiency 90.0 Vbat=3.2V Efficiency(%) 91.0 ACT2802-04 VIN = 5.0V ICHRG = 2.1A ACT2802-03 Efficiency(%) 3.5 100.0 91.5 90.5 90.0 Vbat=3.7V 80.0 Vbat=4.1V 70.0 60.0 50.0 89.5 89.0 40.0 3.0 3.2 3.4 3.6 3.8 4.0 0 4.2 300 600 900 1200 1500 1800 Vbat (V) Output Current (mA) Battery Charge Current VS. Temperature Boost Leakage VS. Temperature (HZ Mode) 3000 25.0 2500 20.0 IBAT (mA) 2000 ACT2802-06 VIN = 5.0V VBAT = 3.5V ACT2802-05 Battery Charge Current (mA) 3.0 Vbat (V) Charge Efficiency 92.0 2.5 1500 15.0 Vbat=3.5V Vbat=4.1V 10.0 1000 5.0 500 0 -20 0 0 20 40 60 80 100 120 140 -20 Temperature (°C) Innovative PowerTM 0 20 40 60 80 100 120 Temperature (°C) - 18 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Schematic as show in Figure 20, Ta = 25°C, unless otherwise specified) Boost Output Voltage VS. Temperature 3000 5.4 Boost Output Voltage (V) 2600 2400 2200 2000 1800 0 20 40 60 80 100 120 5.2 5.1 5.0 4.9 140 -30 0 30 60 90 120 Temperature (°C) Temperature (°C) Boost Output Voltage VS. Output Current Boost Output Constant Current Limit VS. Vbat Vbat=3.2V 4.93 Vbat=4.15V 4.89 4.85 0 500 1000 1500 2000 2500 150 2550 ACT2801-010 ACT2802-09 5.01 4.97 Boost Output Constant Current mA) 5.05 Boost Output Voltage (V) 5.3 4.8 -20 2500 2450 2400 2350 2300 2250 3000 3.0 3.2 3.4 3.6 3.8 4.0 Boost Output Current (mA) Vbat (V) Boost Standby Current VS. Battery Voltage Boost Leakage VS. Battery Voltage (HZ Mode) 4.2 8.0 057 0.53 7.0 Battery Leakage (µA) 0.55 ACT2802-012 ACT2802-011 Standby Current (mA) VBAT = 3.5V VOUT = 5.05V ACT2802-08 VBAT = 3.5V CV= 4.5V Rcs=25mΩ(1%) 2800 ACT2802-07 Boost Output Constant Current (mA) Boost Output Constant Current Limit VS. Temperature 0.51 0.49 0.47 6.0 5.0 4.0 3.0 2.0 1.0 0 0.45 3.0 3.3 3.6 3.9 4.2 45 0 4.8 2.0 3.0 4.0 5.0 Battery Voltage(V) Battery Voltage(V) Innovative PowerTM 1.0 - 19 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (Schematic as show in Figure 20, Ta = 25°C, unless otherwise specified) Boost Load Transient (80mA-1A-80mA) Boost Load Transient (1A-2.1A-1A) CH1 ACT2802-014 VBAT = 4.2V 3.4V V BAT = VOUT = 5.0V 5.0V V OUT = = 1.3A 2.4A IIIOST IOST = ACT2802-013 VBAT = 3.4V VOUT = 5.0V IIOST = 2.4A CH1 CH2 CH2 CH1: VOUT, 100mV/div CH2: IOUT, 1A/div TIME: 1ms/div CH1: VOUT, 100mV/div CH2: IOUT, 1A/div TIME: 1ms/div SW and Output Waveforms in Boost Mode CH1 CH1 ACT2802-016 VBAT = 4.1V VOUT = 5.0V IOUT = 2.4A ACT2802-015 3.4V BAT ==3.4V VVBAT 5.0V OUT ==5.0V VVOUT I = 1.0A OUT IOUT = 2.4A SW and Output Waveforms in Boost Mode CH2 CH2 CH1: VOUT, 20mV/div CH2: VSW, 2V/div TIME: 1us/div CH1: VOUT, 20mV/div CH2: VSW, 2V/div TIME: 1us/div Transition Between Buck Mode and Boost Mode VIN = 5.0V VBAT = 4.1V VIN = 5.0V VBAT = 4.1V VIN VnPG ACT2802-017 CH1 CH2 CH3 Vout CH1: VIN, 5V/div CH2: VnPG, 5V/div CH3: vout, 2V/div TIME: 1s/div Innovative PowerTM - 20 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi. ACT2802 Rev 0, 21-Jan-14 PACKAGE OUTLINE QFN44-24 PACKAGE OUTLINE AND DIMENSIONS SYMBOL DIMENSION IN MILLIMETERS DIMENSION IN INCHES MIN MAX MIN MAX A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.200 REF 0.008 REF b 0.180 0.300 0.007 0.012 D 3.850 4.150 0.152 0.163 E 3.850 4.150 0.152 0.163 D2 2.500 2.800 0.098 0.110 E2 2.500 2.800 0.098 0.110 e L R K 0.500 BSC 0.350 0.450 0.200 TYP 0.200 --- 0.020 BSC 0.014 0.018 0.008 TYP 0.008 --- Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact [email protected] or visit http://www.active-semi.com. is a registered trademark of Active-Semi. Innovative PowerTM - 21 - www.active-semi.com Active-Semi Confidential―Do Not Copy or Distribute Copyright © 2013 Active-Semi, Inc. ActiveSwitcherTM is a trademark of Active-Semi.