Overview
The BQ2002SNTRG4 is a low-cost CMOS battery-charge controller from Texas Instruments, designed for reliable fast charging of nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries. This IC integrates fast charge, optional top-off, and pulsed-trickle control in a single package, making it suitable for both stand-alone and system-integrated charger applications. The BQ2002SNTRG4 ensures safe and efficient charging by monitoring battery voltage and temperature, and it can be configured to terminate the fast charge based on various conditions such as peak voltage detection, negative delta voltage, maximum voltage, maximum temperature, and maximum time.
Key Specifications
| Parameter | Minimum | Typical | Maximum | Unit | Notes |
|---|---|---|---|---|---|
| VCC (Supply Voltage) | 4.0 | 5.0 | 6.0 | V | |
| VDET (-∆V, PVD Detect Voltage) | 1 | 2 | V | ||
| VBAT (Battery Input) | 0 | VCC | V | ||
| VTS (Thermistor Input) | 0.5 * VCC | VCC | V | VTS ≤ VTCO inhibits/terminates fast charge and top-off | |
| VMCV (Maximum Cell Voltage) | 2 ± 5% | V | VBAT ≥ VMCV inhibits/terminates fast charge and top-off | ||
| -∆V (BAT Input Change for -∆V Detection) | -12 ± 3 mV | mV | |||
| PVD (BAT Input Change for PVD Detection) | -2.5 ± 2.5 mV | mV | |||
| TOPR (Operating Ambient Temperature) | 0 | 70 | °C | ||
| TSTG (Storage Temperature) | -40 | 85 | °C | ||
| ICC (Supply Current) | 250 µA | µA | Outputs unloaded, VCC = 5.1V | ||
| ISB (Standby Current) | 1 µA | µA | VCC = 5.1V, VBAT = VPD |
Key Features
- Fast charge of nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries
- Direct LED output displays charge status
- Fast-charge termination by peak voltage detection (PVD), negative delta voltage (-∆V), maximum voltage, maximum temperature, and maximum time
- Internal band-gap voltage reference
- Optional top-off charge and pulsed-trickle charge rates
- Selectable pulse trickle charge rates
- Low-power mode to reduce system power consumption
- Charge inhibit feature using the INH pin
- Battery voltage and temperature monitoring
- Available in 8-pin 300-mil DIP or 150-mil SOIC packages
Applications
- Stand-alone battery chargers
- System-integrated battery chargers
- Portable electronic devices requiring NiCd or NiMH battery charging
- Industrial and consumer electronics where reliable battery charging is critical
- Battery-powered tools and equipment
Q & A
- What types of batteries does the BQ2002SNTRG4 support?
The BQ2002SNTRG4 supports nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries.
- How does the BQ2002SNTRG4 terminate the fast charge cycle?
The fast charge cycle can be terminated by peak voltage detection (PVD), negative delta voltage (-∆V), maximum voltage, maximum temperature, or maximum time.
- What is the purpose of the INH pin on the BQ2002SNTRG4?
The INH pin is used to inhibit the fast charge and top-off activities. When the INH pin is high, it suspends the fast charge and top-off, and when it returns low, the charge control and timer resume from the point where INH became active.
- How does the BQ2002SNTRG4 monitor battery temperature and voltage?
The IC monitors battery temperature using a ground-referenced negative temperature coefficient thermistor and battery voltage through a resistor-divider network connected between the positive and negative terminals of the battery.
- What are the package options for the BQ2002SNTRG4?
The BQ2002SNTRG4 is available in 8-pin 300-mil DIP and 150-mil SOIC packages.
- What is the operating ambient temperature range for the BQ2002SNTRG4?
The operating ambient temperature range is 0°C to 70°C.
- How does the low-power mode work on the BQ2002SNTRG4?
The IC enters a low-power state when VBAT is driven above the power-down threshold (VPD), reducing the operating current to less than 1µA.
- What is the purpose of the LED pin on the BQ2002SNTRG4?
The LED pin displays the charge status, going low during fast charge and to the high-Z state for other conditions.
- Can the BQ2002SNTRG4 be used in both stand-alone and system-integrated chargers?
Yes, the BQ2002SNTRG4 can be used in both stand-alone and system-integrated charger applications.
- What are the typical applications for the BQ2002SNTRG4?
Typical applications include portable electronic devices, industrial and consumer electronics, and battery-powered tools and equipment.
