The LTC3110 is a new product from Linear Technology. It is a bidirectional programmable input current buck-boost supercapacitor charger with active charge balancing for 1 or 2 series supercapacitors. The proprietary low-noise buck-boost topology completes the work of two independent switching regulators, thereby saving size, cost, and complexity.
The LTC3110 works in two modes, standby mode and charging mode. In standby mode, the device maintains the system voltage VSYS powered by the energy stored in the supercapacitor from 1.71V to 5.25V. In addition, the supercapacitor storage input VCAP has a wide practical operating range of 5.5V to 0.1V. This ensures that all the actual stored supercapacitor energy is used, thereby extending the standby time or reducing the storage capacitor.
Or, in the charging mode, when the main power system is active, the LTC3110 can use the adjusted system voltage to reverse the direction of the current autonomously or through user commands to charge and balance the supercapacitor. The buck-boost PWM (pulse width modulator) effectively charges VCAP above or below VSYS. The device also has a charge mode average input current limit, which can be programmed to a maximum of 2A with an accuracy of +/- 2%, which prevents system power overloads while minimizing capacitor charging time.
