TS1108 Coulomb Counter User s Guide The TS1108 coulomb counter accurately measures battery depletion while also indicat- KEY FEATURES ing the battery charging polarity. The battery discharge current is monitored by a cur- rent-sense amplifier through an external sense resistor. Utilizing an Integrator and a R : 50 m 0.5% SENSE Comparator plus a Monoshot, the TS1108 voltage-to-frequency converter provides a series of 90 s output pulses at COUT, which represents an accumulation of coulombs Compatible for Both Gain Options flowing out of the battery. The charge count frequency is adjustable by the integration 20 V/V resistor and capacitor. 200 V/V The TS1108 CSA requires a very low 1.2 A supply current, while also combining a 150 ORDERING INFORMATION V VOS(MAX) with a 0.6% gain error (MAX) for high precision current measurements. The TS1108 provides a buffered CSA output which can be connected with a RC Filter to TS1108-20DB reduce noise. The VDD supply requires a typical supply current of 1.93 A when VREF TS1108-200DB is disabled. The TS1108 is fully specified to operate over the 40 C to +85 C temperature range and is available in a low-profile thermally-enhanced 16-pin 3 x 3 mm TQFN package with an exposed back-side paddle. silabs.com Smart. Connected. Energy-friendly. Rev. 1.0 TS1108 Coulomb Counter User s Guide Description 1. Description The TS1108 Evaluation Board is intended for evaluating the coulomb counter functionality of the TS1108. The TS1108 Coulomb Coun- ter function utilizes an Integrator and a Comparator plus a 90 s Monoshot. The CSAs buffered output is applied to the integrators input. This signal is integrated by the comparator until it reaches a level which trips the comparator. The comparators trip level is deter- mined by the voltage applied to the comparators non-inverting terminal, CIN+. The Monoshot produces a 90 s output pulse at COUT and the integrator is reset. Therefore, each COUT 90 s pulse represents an accumulation of coulombs (Please refer to Coulomb Counter Equations in Applications Information). The TS1108 Integrator works best when the 90 s Monoshot represents less than 2% of the total integration period. Therefore, the minimum integration time for a full-scale V should be limited to 4.7 ms. To guarantee SENSE stable operation of the OUT buffer, an integration capacitance of 0.1 F should be used for integration capacitor, C . The TS1108s INT Coulomb Counting interrupt is provided by the internal comparator with a push-pull output configuration. The following equation can be used to calculate how many ampere-hours (Ah) each comparator interrupt pulse represents: R C V V ( ) INT INT CIN VBIAS Compa rato r Pulse = Ah 3600 GAIN R SENSE Table 1.1. Component List Designation Quantity Description U1 1 TS1108-20, TS1108-200 RS1 1 50 m 0.5%, 1/2 W (1206) C1, C6 2 1 F 10%, 10 V (0603) C2, C4, C7, C9, C10 5 0.1 F 10%, 10 V (0603) C3 1 1 nF 10%, 25 V (0603) C5 1 0.47 F 10%, 10 V (0603) R1 1 4.02 k 1%, 1/16 W (0603) R2 1 47 k 1%, 1/16 W (0603) R4, R5, R6 3 2 M 1%, 1/10 W (0603) J1, J2, J3, J4, J7, J8 6 Header 1x1 JP2, JP3, JP5 3 Header 1x3 JP4, JP6, JP7, JP8, JP9, JP10, JP11, 8 Jumper JP12 JS1, JS2, JS3 3 Jumper Shunt silabs.com Smart. Connected. Energy-friendly. Rev. 1.0 1