CXLB73317 is a Ni-MH battery charging management chip with PWM buck architecture, which supports series charging of 1 to 15 batteries, with a wide input voltage range of 5V-18V, and is compatible with a variety of adapter inputs. The chip is packaged in SOP8, with few peripheral components and simple use. It has a built-in multi-saturation judgment mechanism (including negative pressure detection, zero pressure detection, timing control, etc.). It can be adapted to most nickel-hydrogen batteries on the market and has perfect protection and automatic control functions.
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[ CXLB73317 ]"
CXLB73317 Wide Voltage Input Multi-Section Ni-MH Battery Charge Management IC Comprehensive Analysis and Application Guide
In applications such as portable medical equipment, power tools, small appliances and bright flashlights, efficient, safe and intelligent battery charging management solutions have become the core requirements of product design. As a multi-section Ni-MH battery charging management integrated circuit supporting 5-18V wide voltage input and PWM step-down architecture, CXLB73317 is becoming an ideal choice for engineers in high voltage input and multi-section battery applications with its advantages of high integration, simple periphery and perfect functions. This article will deeply analyze the technical characteristics, working principle, design points and typical applications of the CXLB73317, and help engineers to build a high-performance and high-reliability charging system.
1. CXLB73317 Product overview
CXLB73317 is a Ni-MH battery charging management chip with PWM buck architecture, which supports series charging of 1 to 15 batteries, with a wide input voltage range of 5V-18V, and is compatible with a variety of adapter inputs. The chip is packaged in SOP8, with few peripheral components and simple use. It has a built-in multi-saturation judgment mechanism (including negative pressure detection, zero pressure detection, timing control, etc.). It can be adapted to most nickel-hydrogen batteries on the market and has perfect protection and automatic control functions.
2. Key Features and Benefits
· Wide input voltage range5V-18V, suitable for a variety of industrial and consumer power supply.
· PWM Buck Architecture: Switching frequency 100kHz, high conversion efficiency, low noise.
· Intelligent satiety judgment mechanism: Support negative pressure, zero pressure, the longest charging time and other full way.
· Automatic control function: It has intelligent functions such as plug-in recognition, automatic power supply, and recharge.
· High precision current control: The charging current can be flexibly set by an external resistor, up to 1A.
· Status indication output: CHRG and DONE pins indicate the charging and charging completion status respectively.
· Small size packageSOP8 package for space-constrained scenarios.
3. pin function details
| Pin | Name | Function Description |
|---|---|---|
| 1 | Wine | Input power positive pole, external filter capacitor. |
| 2 | FB | The battery voltage feedback terminal is used to set the output voltage. |
| 3 | CS | Charging current feedback terminal, external current detection resistor. |
| 4 | NC | Suspended, not connected. |
| 5 | DRV | Buck switch MOS tube drive output. |
| 6 | CHRG | Charging status indication, output high level during charging. |
| 7 | DONE | Charging completion indication, output high level after full charge. |
| 8 | GND | Systemically. |
4. working principle and charging process
The CXLB73317 adopts PWM step-down architecture and sets the charging current and output voltage through external resistors to realize intelligent charging management of 1-15 Ni-MH batteries:
4.1. Charging current setting：
The constant current charging current is determined by the CS pin external detection resistor RCS:
4.2. Output voltage setting：
Set the FB pin voltage through R1 and R2 voltage dividing resistors, and the calculation formula of battery full voltage is:
4.3. The recommended configuration is as follows (excerpt):
| Number of batteries | R1 | R2 |
|---|---|---|
| 3 | 200kΩ | 100kΩ |
| 6 | 100kΩ | 20kΩ |
| 9 | 240kΩ | 30kΩ |
| 12 | 330kΩ | 30kΩ |
| 15 | 420kΩ | 30kΩ |
4.4. Full sentence and protection mechanisms.：
The chip supports negative pressure detection (6-10mV), zero pressure hold (60 minutes), and maximum charging time limit (6 hours) to ensure safe and full battery charging.
5. Status Indication Description
The CXLB73317 drives the LED indicator through the CHRG and DONE pins, and the status is as follows:
· CHRG (Pin 6): Output high level during charging, other states are high resistance.
DONE (Pin 7): Output high level after full, other states are high resistance.
6. Typical Application Circuits and BOM Recommendations
The following is an example of the BOM representation for a typical application:
| Category | Position number | Parameters | Description |
|---|---|---|---|
| Resistance | R5 | 0.1Ω 1206 | Current detection resistance |
| Resistance | R1,R2 | Configure by number of batteries | FB voltage dividing resistor |
| Capacitance | C2,C5 | 220μF electrolysis | Input/Output Filtering |
| Capacitance | C3,C4,C8,C9 | 10μF | decoupling capacitor |
| Inductance | L3 | 10μH | power inductance |
| MOS | Q3 | P-MOS SOT23/SOP8 | switch tube |
| Diode | D1,D2 | SS14/SS24 | Schottky diode |
| triode | Q1,Q2,Q8 | 3904/3906 | control circuit |
| LDO | U2 | 5.0V SOT89 | Auxiliary power supply |
| Master Control | U1 | CXLB73317 SOP8 | Main control IC |
7. Design Considerations
7.1. Layout recommendations：
· Current sense resistor R5 should be in close proximity to the CS and GND pins.
· Inductor and switching node (DRV) traces should be short and thick to reduce EMI and switching losses.
· The FB voltage divider network should be close to the chip to avoid noise interference.
7.2. Thermal design：
· Chips and power devices should be arranged in a well-ventilated area, and heat dissipation holes should be added if necessary.
7.3. Input Filtering：
· It is recommended to use electrolytic capacitors in parallel with ceramic capacitors to take into account high-frequency response and energy storage requirements.
8. typical application scenarios
The CXLB73317 is suitable for a variety of high-voltage input, multi-battery charging scenarios, including:
· Portable medical products (e. g. monitors, handheld devices)
· Power tools (e. g. drill, angle grinder)
· Small household appliances (e. g. vacuum cleaners, sweepers)
· Ni-MH battery charger (including seat charger, portable charger)
· Strong flashlight and emergency lighting equipment
9. epilogue
With its wide-voltage input, multi-cell battery support, intelligent satiety mechanism and comprehensive automatic control function, the CXLB73317 has become an ideal choice for high-voltage, multi-cell Ni-MH battery charging management. Whether it is a medical device, power tool or household appliance, the chip can provide a safe, efficient and reliable charging solution. For CXLB73317 samples, technical information or design support, please visitJTM-IC official websiteOr contact our technical support team.
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