TS2208 TSC | Alldatasheet
Document overview
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Technical content
Features
Low current consumption Supply current 3uA (typ) and standby current 0.1uA High withstand voltage up to 22V (VDD ~ V-) High accuracy voltage detection Over charge detector Over discharge detector Over current and short circuit protection Small package of SOT-26
Applications
Over-charge and over-discharge protection for Li-ion cell pack High precision protectors for cell-phones and other gadget using on board Li-ion cell battery Pin Description No. Symbol Description
1 DOUT Output of over discharge detection
2 V- Pin for charger negative input
3 COUT Output of over charge detection
4 CEXT Pin for external capacitor Setting
5 VDD Power supply
6 VSS Ground
- DOUT 2. V- 3. COUT 4. CEXT 5. VDD 6. VSS
TS2208A/B series 2-6 2003/12 rev. B Block Diagram Typical Application
TS2208A/B series 3-6 2003/12 rev. B Absolute Maximum Rating Supply Voltage V DD -0.3 to 12 V V- pin V- V DD-22 to VDD +0.3 V Input Voltage VCT pin VCext V DD-0.3 to VDD +0.3 V COUT pin VC OUT V DD-22 to VDD +0.3 V Output Voltage DOUT pin VD OUT V DD-0.3 to VDD +0.3 V Power Dissipation P D 150 mW Operating Temperature Range T OPT -40 to +85 oC Storage Temperature Range T STG -50 to +120 oC Note: Absolute Maximum ratings are threshold limit values that must not be exceeded even for an instant under any conditions. Operation above these absolute maximum ratings may cause degradation or permanent damage to the device. These are stress ratings only and do not necessarily functional operation below these limits. Electrical Characteristics (Ta = 25 oC, unless otherwise specified.) Parameter Conditions Symbol Min Typ Max Unit Operating input voltage Voltage defined as V DD-VSS V DD1 1.5 -- 10 V TS2208A 4.33 4.35 4.37 Over-charge threshold voltage Detect rising edge of supply voltage TS2208B V 4.26 4.28 4.30 V Over-charge threshold hysteresis range V HYS 0.15 0.20 0.25 V Over-charge delay time C3= 0.01µF, VDD = 3.6V to 4.4V tC1 60 75 90 ms Over-discharge threshold voltage Detect falling edge of supply voltage VD1 2.437 2.500 2.563 V Over-discharge delay time V DD= 3.6V to 2.4V t D1 7 10 13 ms Over current detection voltage Detect rising edge of “V-” pin voltage VOC 0.17 0.20 0.23 V Over current detection delay time V DD= 3.0V t OC 9 14 17 ms Short circuit detection voltage V DD= 3.0V Vshort V DD-1.2 V DD-0.9 V DD-0.6 V Short circuit detection delay time V DD= 3.0V tshort -- 5 50 µS Reset resistance for excess current protection VDD= 3.6V,V-=1.0V Rshort 50 100 150 K Ω Nch ON voltage of COUT I OL = 50µA, VDD= 4.4V V OL1 -- 0.3 0.5 V Pch ON voltage of COUT I OH = -50µA, VDD= 3.9V V OH1 3.4 3.8 -- V Nch ON voltage of COUT I OH = 50µA, VDD= 2.4V V OL2 -- 0.2 0.5 V Pch ON voltage of COUT I OH= -50µA, VDD= 3.9V V OH2 3.4 3.7 -- V Supply current V DD= 3.9V,V-= 0V I DD -- 3 5 µA Standby current V DD= 2.0V I standby -- -- 0.1 µA
TS2208A/B series 4-6 2003/12 rev. B Operation Description COM1 (Over-Charge Detector) COM1 is the monitor of the voltage at the V DD pin. COM1 senses an over charging condition and if this condition continues longer than the delay time (t C1), When the voltage at V DD exceeds the over charge detector threshold V C1. the COUT pin goes to a “L” level thus turns off the external charge control N-ch MOSFET. An internal level shifter is incorporated in the buffer driver at the C OUT pin to drive the “L” level of COUT equal to the V- pin voltage. By the way, the “H” level of COUT is set equal to VDD. The delay time (tC1) of over-charging is decided by the external capacitor C3 connected between the Vss and Cext pin, it can be estimated as tC1 = [C3 x (VDD-0.7)] / (0.48 x 10 -6). However, if the over-charge condition doesn’t last long enough to cover the time delay window, COUT will not go “L” and the charging process continues. Required Conditions to Reset COM1 from Over Charging After the MOSFET, the charge control is turns off, COM1 can be reset under two conditions. As resetting COM1 means COUT returns to “H” again and the charging path is reconnected to restart of charging process. One of the condition to reset COM1 is when V DD falls to lower than “V C1 - V HYS” as a result of battery cell internal discharge. Disconnecting the battery pack from the charger can also reset COM1 even when V DD is still within the hysteresis window (VC1 - VHYS ≤VDD < VC1). After the battery pack is disconnected from the charger, connecting a system load to the battery pack allows current to flow through the parasitic diode of external charge control MOSFET. This discharging current will bring V DD down a little over some time and once VDD drops below VC1, COUT will become “H”. COM2 (Over-Discharge Detector) COM2 monitors the cell voltage at the V DD pin. When V DD drops below the over-discharge threshold V D2 during the discharging process, COM1 senses an over-charging condition and after delay time (t D1), the D OUT pin goes to a “L” level and thus turning off the external discharge control N-ch MOSFET. As soon as this happens, the V- pin will be pulled “H” by an internal PMOS and TS2208A/B series will be enter a standby mode. Connecting the battery pack to a charger is a necessary condition for TS2208A/B series to recover from standby mode. With the charger connected, the charge current can flow through the parasitic diode of the external discharge control N-ch MOSFET while V DD is still lower than the over-discharge threshold. Once V DD is charged up to a value higher than V D1, the D OUT pin goes “H”. This leads to the “ON” state of both the charge and discharge control MOSFETs, and the charge process proceeds on as long as the charger is connected. Connecting a charger to the battery pack when VDD voltage is already higher then VD1 will make DOUT instantaneously “H”. COM3 (Over Current Detector, Short Circuit Protector) The over current detector and short circuit protector can work when both the charge and discharge control N-ch MOSFETs are “ON”. Under normal operation, the V- pin voltage will be eith er slightly higher or lower than Vss (dependent on the impedance of the two MOSFETs). However, when the V- pin voltage rises to a value between the short protection voltage Vshort and over current threshold V OC, the TS2208A/B series detect an excess current condition. As a result, the external discharge control N-ch MOSFET goes “OFF” with the DOUT pin being at “L”. An output delay time for the over current detection is internally fixed. A quick recovery of V- from a value between Vshort and V OC to the normal value within the delay time keeps the discharge control FET staying at the “ON” state. Short circuit may as well be explained as a “serious” over current condition. When the V- pin voltage rises to a value not only higher than V OC but also higher than Vshort, the short circuit protector will shut the discharge MOSFET down immediately to protect battery pack from being damaged or exploding. The V- pin has a built-in pull down resistor. Thus once the cause of over current or short circuit is removed, the V- pin will be pulled down to the ground level through the internal resistor. Therefore, with V- lower than the over current and short circuit protection threshold, D OUT will be turned back on and the TS2208A/B series can continue normal charge or discharge operation. Notice that when over current or short circuit occurs, the TS2208A/B series will not enter a standby mode.
TS2208A/B series 5-6 2003/12 rev. B Timing Diagram
TS2208A/B series 6-6 2003/12 rev. B SOT-26 Mechanical Drawing SOT-26 DIMENSION MILLIMETERS INCHES DIM MIN MAX MIN MAX A 2.70 3.00 0.106 0.118 B 0.25 0.50 0.010 0.020 C 1.90(typ) 0.075(typ) D 0.95(typ) 0.037(typ) E 1.50 1.70 0.059 0.067 F 1.05 1.35 0.041 0.053 H 2.60 3.00 0.102 0.118 L 0.60(typ) 0.024(typ)