Datasheet LTC4150 (Analog Devices) - 10

LTC4150
APPLICATIONS INFORMATION AUTOMATIC CHARGE COUNT INTERRUPT AND CLEAR
use Figure 6. The resistor dividers on CLR and SHDN keep the voltages at these pins within the LTC4150’s V In applications where a CLR pulse is unavailable, it’s easy to DD range. Choose an R make the LTC4150 run autonomously, as shown in Figures L value using Equation 11 and R1-R4 values using Equation 13. In either application, the LTC4150 will 5 and 6. If the microcontroller VCC is less than or equal to capture the fi rst assertion of INT and wait at least 1μs the battery VDD, INT may be directly connected to CLR, as before resetting it. This insures that INT pulses low for at in Figure 5. The only requirement is that the microcontroller least 1μs but gives automatic INT reset. should be able to provide a high logic level of 1.9V to SHDN. If the microcontroller VCC is greater than the battery VDD, POWER-DOWN SWITCH LOAD PROCESSOR CL V 47μF CC RL RL 1 10 SENSE+ INT 9 R LTC4150 SENSE CLR 8 2 SENSE– VDD C2 + 3 2.7V TO 8.5V + 7 4.7μF CF GND BATTERY μP CF 4.7μF 4 C –F 5 6 SHDN POL 4150 F05
Figure 5. Application with INT Direct Drive or CLR and Separate Microprocessor Supply VCC ≤ VDD
POWER-DOWN SWITCH LOAD PROCESSOR CL V 47μF CC RL RL 1 10 SENSE+ INT 9 R LTC4150 SENSE CLR R2 8 2 SENSE– VDD C2 + 3 + 7 4.7μF BATTERY CF GND R1 μP VBATTERY < VCC CF 4.7μF 4 C –F 5 6 SHDN POL SHUTDOWN R4 R3 4150 F06
Figure 6. Application with INT Driving CLR and Separate Microprocessor Supply VCC > VDD
4150fc 10 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM TIMING DIAGRAMS OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS