XB5351A
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One Cell Lithium-ion/Polymer Battery Protection IC
GENERAL DESCRIPTION
The XB5351 series product is a high integration solution for lithium-ion/polymer battery protection. XB5351 contains advanced power MOSFET, high-accuracy voltage detection circuits and delay circuits. XB5351 is put into an ultra-small SOT23-5 package and only one external component makes it an ideal solution in limited space of battery pack.
XB5351 has all the protection functions required in the battery application including overcharging, overdischarging, overcurrent and load short circuiting protection etc. The accurate overcharging detection voltage ensures safe and full utilization charging. The low standby current drains little current from the cell while in storage.
The device is not only targeted for digital cellular phones, but also for any other Li-Ion and Li-Poly battery-powered information appliances requiring long-term battery life.
FEATURES
· Protection of Charger Reverse Connection
· Protection of Battery Cell Reverse Connection
· Integrate Advanced Power MOSFET with Equivalent of 54m Ω R DS(ON) · Ultra-small SOT23-5 Package · Only One External Capacitor Required
· Over-temperature Protection · Overcharge Current Protection · Two-step Overcurrent Detection: -Overdischarge Current -Load Short Circuiting · Charger Detection Function · 0V Battery Charging Function - Delay Times are generated inside · High-accuracy Voltage Detection · Low Current Consumption
- Operation Mode: 2.8μA typ. - Power-down Mode: 0.1μA max. · RoHS Compliant and Lead (Pb) Free
APPLICATIONS
• One-Cell Lithium-ion Battery Pack • Lithium-Polymer Battery
Pack
Figure 1. Typical Application Circuit
ORDERING INFORMATION
PART NUMBER Pack
age Overcharg e Detection Voltage [V CU ] (V) Overcharge Release Voltage [V CL ] (V) Overdischarge Detection Voltage [V DL ] (V) Overdischarge Release Voltage [V DR ] (V) Overcurrent
Detection
Current
[I OV1] (A) Top Mark
XB5351A
SOT
23-5
4.30
4.10
2.40
3.0
5351AYW (note)
Note: “YW” is manufacture date code, “Y” means the year, “W” means the week
PIN CONFIGURATION
Figure 2. PIN Configuration
PIN DESCRIPTION
XB5351 PIN NUMBER
PIN NAME
PIN DESCRIPTION
1 V T Test pin ；only for vendor not used by application 2
GND
Ground, connect the negative terminal of the battery to this pin
3 VDD Power Supply
4,5 VM
The negative terminal of the battery pack. The internal FET switch connects this terminal to GND
ABSOLUTE MAXIMUM RATINGS
(Note: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability.) PARAMETER VALUE UNIT
VDD input pin voltage -0.3 to 6 V VM input pin voltage
-6 to 10 V Operating Ambient Temperature -40 to 85
°C
Maximum Junction Temperature
125 °C
Storage Temperature-55 to 150 °C
Lead Temperature ( Soldering, 10 sec)300 °C Power Dissipation at T=25°C 0.4 W
Package Thermal Resistance (Junction to Ambient) θJA250 °C/W Package Thermal Resistance (Junction to Case) θJC130 °C/W ESD 2000 V
ELECTRICAL CHARACTERISTICS
Typicals and limits appearing in normal type apply for T A=25o C, unless otherwise specified
Parameter Symbol Test Condition Min Typ Max Unit
Detection Voltage
Overcharge Detection Voltage V CU
4.25 4.30 4.35V
Overcharge Release Voltage V CL 4.05 4.10 4.15
V
Overdischarge Detection Voltage V DL 2.3 2.4 2.5广州
黄埔造船厂
V
Overdischarge Release Voltage V DR 2.9 3.0 3.1
V
Charger Detection Voltage V CHA-0.07-0.12 -0.2V Detection Current
Overdischarge Current1 Detection I
高志林
IOV1
V DD=3.5V 2.1 3 3.9A Load Short-Circuiting
Detection
I SHORT V DD=3.5V 10 2030 A Current Consumption
Current Consumption in Normal Operation I OPE V DD=3.5V
VM =0V
2.8 6 μA甘精胰岛素
Current Consumption in power Down I PDN V DD=2.0V
VM pin floating
0.1 μA
VM Internal Resistance
Internal Resistance between VM and V DD R VMD V DD=3.5V
VM=1.0V
320
kΩ
Internal Resistance between VM and GND R VMS V DD=2.0V
VM=1.0V
100
kΩ
FET on Resistance
Equivalent FET on Resistance R DS(ON)V DD=3.6V I VM=1.0A5463
mΩ
Over Temperature Protection
Over Temperature Protection T SHD+120
Over Temperature Recovery Degree T SHD-100
o C
Detection Delay Time
Overcharge Voltage Detection
Delay Time
t CU 130 200 mS
Overdischarge Voltage Detection
Delay Time
t DL 40 60 mS
Overdischarge Current Detection
t IOV V DD=3.5V 15 20 mS
Load Short-Circuiting Detection
Delay Time
t SHORT V DD=3.5V 180 300 uS
Figure 3. Functional Block Diagram
FUNCTIONAL DESCRIPTION
The XB5351 monitors the voltage and current of a battery and protects it from being damaged due to overcharge voltage, overdischarge voltage, overdischarge current, and short circuit conditions by disconnecting the battery from the load or charger. These functions are required in order to operate the battery cell within specified limits.
The device requires only one external capacitor. The MOSFET is integrated and
its R DS(ON)is as low as54mΩtypical. Normal operating mode
寻成龙
首映
If no exception condition is detected, charging and discharging can be carried out freely. This condition is called the normal operating mode.
Overcharge Condition
When the battery voltage becomes higher than the overcharge detection voltage (V CU) during charging under normal condition
and the state continues for the overcharge detection delay time (t CU) or longer, the
XB5351 turns the charging control FET off
to stop charging. This condition is called the overcharge condition. The overcharge condition is released in the following two cases:
1, When the battery voltage drops below the overcharge release voltage (V CL), the XB5351 turns the charging control FET on and returns to the normal condition.
2, When a load is connected and discharging starts, the XB5351 turns the charging control FET on and returns to the normal condition. The release mechanism is as follows: the discharging current flows through an internal parasitic diode of the charging FET immediately after a load is connected and discharging starts, and the VM pin voltage increases about 0.7 V (forward voltage of the diode) from the GND pin voltage momentarily. The XB5351 detects this voltage and releases the overcharge condition. Consequently, in the case that the battery voltage is equal to or lower than the overcharge detection voltage (V CU), the XB5351returns to the normal condition immediately, but in the case the battery voltage is higher than the overcharge detection voltage (V CU),the chip does not return to the normal condition until the battery voltage drops below the overcharge detection voltage (V CU) even if the load is connected. In addition, if the VM pin voltage is equal to or lower than the overcurrent 1 detection voltage when a load is connected and discharging starts, the chip does not return to the normal condition.
Remark If the battery is charged to a voltage higher than the overcharge detection voltage (V CU) and the battery voltage does not drops below the overcharge detection voltage (V CU) even when a heavy load, which causes an overcurrent, is connected, the overcurrent 1 and overcurrent 2 do not work until the battery voltage drops below the overcharge detection voltage (V CU). Since an actual battery has, however, an internal impedance of several dozens of mΩ, and the battery voltage drops immediately after a heavy load which causes an overcurrent is connected, the overcurrent 1 and overcurrent 2 work. Detection of load short-circuiting works regardless of the battery voltage.
Overdischarge Condition
When the battery voltage drops below the overdischarge detection voltage (V DL) during discharging under normal condition and it continues for the overdischarge detection delay time (t DL) or longer, the
XB5351 turns the discharging control FET off and stops discharging. This condition is called overdischarge condition. After the discharging control FET is turned off, the VM pin is pulled up by the R VMD resistor between VM and VDD in XB5351. Meanwhile when VM is bigger than 1.5
V (typ.) (the load short-circuiting detection voltage), the current of the chip is reduced to the power-d
own current (I PDN). This condition is called power-down condition. The VM and VDD pins are shorted by the
R VMD resistor in the IC under the overdischarge and power-down conditions. The power-down condition is released when a charger is connected and the potential difference between VM and VDD becomes 1.3 V (typ.) or higher (load short-circuiting detection voltage). At this time, the FET is still off. When the battery voltage becomes the overdischarge detection voltage (V DL) or higher (see note), the XB5351 turns the FET on and changes to the normal condition from the overdischarge condition.
Remark If the VM pin voltage is no less than the charger detection voltage (V CHA), when the battery under overdischarge condition is connected to a charger, the overdischarge condition is released (the discharging control FET is turned on) as usual, provided that the battery voltage reaches the overdischarge release voltage (V DU) or higher. Overcurrent Condition
When the discharging current becomes equal to or higher than a specified value (the VM pin voltage is equal to or higher than the overcurrent detection voltage)
during discharging under normal condition and the state continues for the overcurrent detection dela
y time or longer, the XB5351 turns off the discharging control FET to stop discharging. This condition is called overcurrent condition. (The overcurrent includes overcurrent, or load short-circuiting.)
The VM and GND pins are shorted internally by the R VMS resistor under the overcurrent condition. When a load is connected, the VM pin voltage equals the VDD voltage due to the load.
The overcurrent condition returns to the normal condition when the load is released and the impedance between the B+ and B- pins becomes higher than the automatic recoverable impedance. When the load is removed, the VM pin goes back to the GND potential since the VM pin is shorted the GND pin with the R VMS resistor. Detecting that the VM pin potential is lower than the overcurrent detection voltage
(V IOV), the IC returns to the normal condition.
Abnormal Charge Current Detection
If the VM pin voltage drops below the charger detection voltage (V CHA) during charging under the normal condition and it continues for the overcharge detection delay time (t CU) or longer, the XB5351 turns the charging control FET off and stops charging. This action is called abnormal charge current detection.
Abnormal charge current detection works when the discharging control FET is on and the VM pin voltage drops below the charger detection voltage (V CHA). When an abnormal charge current flows into a battery in the overdischarge condition, the XB5351 consequently turns the charging control FET off and stops charging after the battery voltage becomes the overdischarge detection voltage and the overcharge detection delay time (t CU) elapses.
Abnormal charge current detection is released when the voltage difference between VM pin and GND pin becomes lower than the charger detection voltage (V CHA) by separating the charger. Since the 0 V battery charging function has higher priority than the abnormal charge current detection function, abnormal charge current may not be detected by the product with the 0 V battery charging function while the battery voltage is low.
Load Short-circuiting condition
If voltage of VM pin is equal or below short circuiting protection voltage (V SHORT), the XB5351 will stop discharging and battery is disconnected from load. The maximum delay time to switch current off is t SHORT. This status is released when voltage of VM pin is higher than short protection voltage (V SHORT), such as when disconnecting the load.
Delay Circuits
The detection delay time for overdischarge current 2 and load short-circuiting starts when overdischarge current 1 is detected. As soon as overdischarge current 2 or load short-circuiting is detected over detection delay time for overdischarge current 2 or load short- circuiting, the XB5351 stops discharging. When battery voltage falls below overdischarge detection voltage due to overdischarge current, the XB5351 stop discharging by overdischarge current detection. In this case the recovery of battery voltage is so slow that if battery voltage after overdischarge voltage detection delay time is still lower than overdischarge detection voltage, the XB5351 shifts to power-down.
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