DEMO MANUAL DC1812A LTC2943/LTC2943-1/LTC2944 Multicell Battery Gas Gauge with Temperature, Voltage and Current Measurement Description Demonstration circuit 1812A-A (Figure 1) features the The LTC2943-1, however, has an integrated sense resistor LTC 2943. Demonstration circuit 1812A-B features the of 50m which sets the maximum current measurement LTC2944. Demonstration circuit 1812A-C features the to 1A. The default value assembled on the DC1812A-A and LTC2943-1. The LTC2943/LTC2943-1 has an operating DC1812A-B is 100m for a maximum current measure- range of 3.6V to 20V, while the LTC2944 has an operating ment of 500mA. The DC1812A-C which showcases the range of 3.6V to 60V, making all three devices perfectly LTC2943-1 has the onboard sense resistor omitted in favor suited for multicell battery applications. A precision analog of the integrated 50m sense resistor. All three parts have coulomb counter integrates current measured through a a software-congurable charge complete/alert pin. When sense resistor between the batterys positive terminal and the pin is set for charge complete, a jumper connects the load or charger. The LTC2943/LTC2943-1 measures the pushbutton which simulates a logic low input at the voltage, current and temperature with an internal 14-bit AL/CC pin. This sets the ACR register to FFFFh which No Latency ADC. The LTC2944 measures voltage, indicates a full battery. When the pin is congured for current and temperature with an internal 16-bit No Latency alert, the same jumper is used to connect a red LED that ADC. The measurements are stored in internal registers indicates an alert is present. 2 accessible via the onboard SMBus/I C interface. The DC1812A is a part of the QuikEval system for quick The LTC2943/LTC2943-1/LTC2944 has programmable evaluation with a host controller through a PC using the high and low thresholds for all measured quantities. If a DC590 or DC2026. programmed threshold is exceeded, the device reports an Design files for this circuit board are available at alert using either the SMBus alert protocol or by setting a DEMO MANUAL DC1812A Quick s p D Demonstration circuit 1812A is easy to set up to evaluate resistor present on the DC1812A-A and DC1812A-B. the performance of the LTC2943/LTC2943-1/LTC2944. The DC1812A-C can support currents of up to 1A with + Refer to Figure 2 for proper measurement equipment its integrated 50m sense resistor. Use SENSE and setup and follow the procedure below. SENSE test points to read voltage across the sense resistor. 1. Connect a Li-Ion battery across V BAT and GND. Mul- tiple Li-Ion batteries can also be used as long as the 4. Connect a DC590 to 14-pin connector J1 for evaluation 2 total voltage does not exceed the operating voltage of with QuikEval, or connect a host controller I C bus to the device. The LTC2943/LTC2943-1 has a maximum the SDA, SCL and GND test turrets. operating voltage of 20V, so for a 4.2V lithium ion 2 5. If a host I C controller is used, then provide a bus pull-up battery the maximum cell count would be 4 cells. The voltage to the +5V turret, else start QuikEval software LTC2944 has a maximum operating voltage of 60V, so on PC. for a 4.2V lithium-ion battery the maximum cell count 6. Read and write to the LTC2943/LTC2943-1/LTC2944 would be 14 cells. 2 through I C. 2. Connect a load across V CHRG/LD and GND for battery 2 7. Through I C, configure the AL/CC pin. Set JP1 accord- discharge measurement. ingly. 3. Connect 3.6V to 20V (LTC2943/LTC2943-1) or 8 If AL/CC is set for charge complete, use pushbutton 3.6V to 60V (LTC2944) battery charger supply switch S1 to simulate a logic low from a controller to across V CHRG/LD and GND for battery charge mea- indicate a fully charged battery. surement. Up to 500mA supplied to the battery can be measured with the board default 100m sense Figure 2. DC1812A Basic Setup dc1812afa 2 ure roce tart