CXLB73314 is a high-precision, multi-functional Ni-MH battery charging management chip, using SOP8/PP package, internal integrated power transistor, no external current detection resistor and blocking diode, greatly simplifying the design of peripheral circuits. The chip supports a maximum charging current of 1A, which can be flexibly set by the user through an external resistor. Its built-in high-precision voltage comparator can accurately control all stages of the charging process to ensure safe and full battery charging.
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[ CXLB73314 ]"
CXLB73314 Ni-MH Battery Charge Management IC Depth Interpretation and Application Guide
With the increasing popularity of portable electronic devices, efficient, safe and intelligent battery charging management solutions have become an indispensable part of product design. As a linear charge management integrated circuit designed for 1 to 3 Ni-MH batteries, CXLB73314 is widely used in digital cameras, electronic dictionaries, portable devices and other fields because of its high integration, simple peripheral and complete functions. This article will comprehensively introduce the technical characteristics, working principle, design points and typical applications of the CXLB73314 to help engineers build a high-performance and high-reliability charging system.
1. CXLB73314 Product overview
CXLB73314 is a high-precision, multi-functional Ni-MH battery charging management chip, using SOP8/PP package, internal integrated power transistor, no external current detection resistor and blocking diode, greatly simplifying the design of peripheral circuits. The chip supports a maximum charging current of 1A, which can be flexibly set by the user through an external resistor. Its built-in high-precision voltage comparator can accurately control all stages of the charging process to ensure safe and full battery charging.
2. Key Features and Benefits
· Wide Range Input Voltage: 3.8V-6V, adapt to a variety of power input.
· High precision voltage control: The voltage accuracy is 1%, and the charging termination voltage is accurately controllable.
· Intelligent charging management: Support trickle, constant current, maintain charging three stages, with automatic recharge function.
· Temperature monitoring and protection: Built-in battery temperature monitoring, support NTC sensor, prevent over-temperature or low-temperature charging.
· Low power sleep mode: Automatically enter sleep mode when the input voltage is powered down, and the battery current consumption is <3μA.
· Thermal modulation control: Automatic current limit when the junction temperature exceeds 135 ℃ to prevent the chip from overheating.
· Status indication output: CHRG pin supports LED driver or MCU interface, real-time display of charging status.
3. pin function details
| Pin | Name | Function Description |
|---|---|---|
| 1 | TEMP | Battery temperature detection input, connected to the NTC sensor, support temperature protection function. |
| 2 | ISET | Charging current setting terminal, external resistor set constant current charging current. |
| 3 | GND | Systemically. |
| 4 | Wine | Input power positive. |
| 5 | BAT | Battery positive connection terminal, providing charging current. |
| 6 | RC | Maintain charging timing setting terminal, external RC network set to maintain charging time. |
| 7 | CHRG | Charge status indication output (open drain). |
| 8 | FB | Battery voltage feedback input for voltage division sampling. |
4. working principle and charging process
The CXLB73314 adopts a three-stage charging strategy to ensure safe and efficient battery charging process:
4.1 trickle charge
When FB voltage <0.843V (battery voltage <70% full voltage), small current pre-charging with 10% of the set current is suitable for low-power batteries.
4.2 constant current charging
When the FB voltage is between 0.843V-1.124V, it enters the constant current charging phase, and the charging current is set by the external resistor of ISET pin:
4.3 maintain charge
When the FB voltage> 1.124V, switch to the maintenance charging mode, the current is 60% of the constant current phase, and start the internal timer. The timing time is determined by the external R and C of the RC pin:
After charging, if the battery voltage drops to 1.084V (about 90% full voltage), the charging cycle is automatically restarted to realize intelligent maintenance.
5. key design points
1. Battery voltage feedback network design
The battery voltage is fed back to FB pin through R3 and R4 voltage division, and the full voltage calculation formula is:
It is recommended that R3/R4 use metal film resistors with 1% accuracy to ensure accurate voltage detection.
2. Temperature monitoring circuit configuration
The TEMP pin is connected to the NTC thermistor and cooperates with R1 and R2 to form a voltage divider network. If you are only concerned with overheat protection, you can simplify the design by using only R1.
3. Maintain the charging time setting
The timing resistor R5 is recommended to be between 20kΩ-1MΩ, and the timing capacitor C1 should be> 1nF, preferably 1μF or 2.2μF 0805/1206 package ceramic capacitor.
4. Heat dissipation and PCB layout
· The EPAD at the bottom of the chip should be soldered to a large area of copper skin to enhance heat dissipation.
· ISET, FB, VIN, BAT and other key signal traces should be short and thick.
· The NTC sensor should be kept away from the chip to avoid being affected by its heat.
6. typical application scenarios
CXLB73314 charge management for a wide range of portable devices, including:
· Digital Cameras and Video Cameras
· Electronic Dictionary and Learning Machine
· Bluetooth speaker, portable audio
· Electric toys and remote control model
· Emergency lighting and low voltage energy storage equipment
Brief 7. Design Process
· Set battery full pressure: Set V_BAT according to the number of battery sections, such as 1.45V for a single section.
· Calculate the R3/R4 ratio: Determine the voltage dividing resistance according to V_BAT = 1.205 × (1R3/R4).
· Select charging current: Set I _CH according to the battery capacity and calculate R_ISET.
· Set maintenance charge time: Calculate R5 and C1 values according to battery capacity and holding current.
· Configure Temperature ProtectionConfigure R1, R2 (if needed) according to NTC characteristics.
8. epilogue
With its high integration, precise voltage control, perfect protection mechanism and flexible configurability, CXLB73314 become the ideal choice for Ni-MH battery charging management. Whether it is a single-cell or multi-cell series application, the chip can provide a safe, efficient and reliable charging solution. For CXLB73314 samples, technical information or design support, please visitJTM-IC official websiteOr contact our technical support team.
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