Datasheet LT1510, LT1510-5 (Analog Devices) - 6
| Manufacturer | Analog Devices |
| Description | Constant-Voltage/Constant-Current Battery Charger |
| Pages / Page | 16 / 6 — TYPICAL PERFORMANCE CHARACTERISTICS. Switch Current vs Boost Current. … |
| File Format / Size | PDF / 297 Kb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS. Switch Current vs Boost Current. Reference Voltage vs. VBOOST vs. vs Boost Voltage
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LT1510/LT1510-5
W U TYPICAL PERFORMANCE CHARACTERISTICS Switch Current vs Boost Current Reference Voltage vs VBOOST vs vs Boost Voltage Temperature Maximum Duty Cycle
50 2.470 96 45 VCC = 16V 95 2.468 40 VBOOST = 38V 94 28V 35 18V 93 2.466 30 92 25 2.464 91 20 90 2.462 BOOST CURRENT (mA) 15 89 REFERENCE VOLTAGE (V) 10 MAXIMUM DUTY CYCLE (%) 88 2.460 5 87 0 2.458 86 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 25 50 75 100 125 150 2 4 6 8 10 12 14 16 18 20 22 SWITCH CURRENT (A) TEMPERATURE (°C) VBOOST (V) 1510 G07 1510 G14 LT1510 • TPC15
U U U PIN FUNCTIONS GND:
Ground Pin.
BAT:
Current Amplifier CA1 Input.
SW:
Switch Output. The Schottky catch diode must be
PROG:
This pin is for programming the charging current placed with very short lead length in close proximity to SW and for system loop compensation. During normal opera- pin and GND. tion, VPROG stays close to 2.465V. If it is shorted to GND the switching will stop. When a microprocessor-controlled
VCC:
Supply for the Chip. For good bypass, a low ESR DAC is used to program charging current, it must be capacitor of 10µF or higher is required, with the lead length capable of sinking current at a compliance up to 2.465V. kept to a minimum. VCC should be between 8V and 28V and at least 2V higher than VBAT for VBAT less than 10V, and
VC:
This is the control signal of the inner loop of the current 2.5V higher than VBAT for VBAT greater than 10V. Under- mode PWM. Switching starts at 0.7V and higher VC voltage lockout starts and switching stops when VCC goes corresponds to higher charging current in normal opera- below 7V. Note that there is a parasitic diode inside from tion. A capacitor of at least 0.1µF to GND filters out noise SW pin to VCC pin. Do not force VCC below SW by more and controls the rate of soft start. To shut down switching, than 0.7V with battery present. All VCC pins should be pull this pin low. Typical output current is 30µA. shorted together close to the pins.
OVP:
This is the input to the amplifier VA with a threshold
BOOST:
This pin is used to bootstrap and drive the switch of 2.465V. Typical input current is about 50nA into pin. For power NPN transistor to a low on-voltage for low power charging lithium-ion batteries, VA monitors the battery dissipation. In normal operation, VBOOST = VCC + VBAT voltage and reduces charging current when battery volt- when switch is on. Maximum allowable VBOOST is 55V. age reaches the preset value. If it is not used, the OVP pin should be grounded.
SENSE:
Current Amplifier CA1 Input. Sensing can be at either terminal of the battery. Note that current sense resistor RS1 (0.08Ω) is between Sense and BAT pins. 6
W U TYPICAL PERFORMANCE CHARACTERISTICS Switch Current vs Boost Current Reference Voltage vs VBOOST vs vs Boost Voltage Temperature Maximum Duty Cycle
50 2.470 96 45 VCC = 16V 95 2.468 40 VBOOST = 38V 94 28V 35 18V 93 2.466 30 92 25 2.464 91 20 90 2.462 BOOST CURRENT (mA) 15 89 REFERENCE VOLTAGE (V) 10 MAXIMUM DUTY CYCLE (%) 88 2.460 5 87 0 2.458 86 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0 25 50 75 100 125 150 2 4 6 8 10 12 14 16 18 20 22 SWITCH CURRENT (A) TEMPERATURE (°C) VBOOST (V) 1510 G07 1510 G14 LT1510 • TPC15
U U U PIN FUNCTIONS GND:
Ground Pin.
BAT:
Current Amplifier CA1 Input.
SW:
Switch Output. The Schottky catch diode must be
PROG:
This pin is for programming the charging current placed with very short lead length in close proximity to SW and for system loop compensation. During normal opera- pin and GND. tion, VPROG stays close to 2.465V. If it is shorted to GND the switching will stop. When a microprocessor-controlled
VCC:
Supply for the Chip. For good bypass, a low ESR DAC is used to program charging current, it must be capacitor of 10µF or higher is required, with the lead length capable of sinking current at a compliance up to 2.465V. kept to a minimum. VCC should be between 8V and 28V and at least 2V higher than VBAT for VBAT less than 10V, and
VC:
This is the control signal of the inner loop of the current 2.5V higher than VBAT for VBAT greater than 10V. Under- mode PWM. Switching starts at 0.7V and higher VC voltage lockout starts and switching stops when VCC goes corresponds to higher charging current in normal opera- below 7V. Note that there is a parasitic diode inside from tion. A capacitor of at least 0.1µF to GND filters out noise SW pin to VCC pin. Do not force VCC below SW by more and controls the rate of soft start. To shut down switching, than 0.7V with battery present. All VCC pins should be pull this pin low. Typical output current is 30µA. shorted together close to the pins.
OVP:
This is the input to the amplifier VA with a threshold
BOOST:
This pin is used to bootstrap and drive the switch of 2.465V. Typical input current is about 50nA into pin. For power NPN transistor to a low on-voltage for low power charging lithium-ion batteries, VA monitors the battery dissipation. In normal operation, VBOOST = VCC + VBAT voltage and reduces charging current when battery volt- when switch is on. Maximum allowable VBOOST is 55V. age reaches the preset value. If it is not used, the OVP pin should be grounded.
SENSE:
Current Amplifier CA1 Input. Sensing can be at either terminal of the battery. Note that current sense resistor RS1 (0.08Ω) is between Sense and BAT pins. 6
