The XC9143/44 is a 18V 1.0A synchronous step-up DC/DC converter that can operate within a wide range of 1.7V~16V and can support output voltages of between 7.0V~18V (set externally). There are two switching frequency options available, 1.2MHz and 3.0MHz and this new boost DC/DC can support output currents of up to 400mA (VOUT=7.0V, VIN=3.3V) or 400mA (VOUT=12V, VIN=5.0V)
This new synchronous boost DC/DC is an ideal solution for use in a variety of applications where there is a requirement to step-up from either a battery or DC inputs such as 5V and 12V to power displays, motors, actuators, or various analogue circuits.
An efficient step-up circuit can be configured using only a minimum of external components and a small 2.2uH inductor (3MHz version) which also helps reduce output ripple voltage - see Fig.1 below:
(Fig.1: Typical Application Circuit)
Powered by a re-chargeable Li-Ion single cell battery (3.7V), a typical IoT sensor application will require not just a charger IC, a step-down DC/DC or LDO for managing power to the MCU and/or sensor, but probably an efficient boost DC/DC to step-up from the battery to 12V @ 200mA for possibly powering OLEDs, LEDs or a motor. The XC9143/44 is ideal for this boost function and the typical power schematic for such a sensor is shown in Fig.2:
(Fig.2: IoT Sensor Schematic)
Power is typically from either a 24V or 12V rail. If the power line is 24V, a buck DC/DC would be required to initially step-down to 5.0V, for example, and then the XC9143/44 can be implemented to step-up to 16V. If, on the other hand, the power rail is 12V then this can be directly connected to the VIN pin of the XC9143/44 to step-up to 16V. A typical power schematic for such a sensor is shown in Fig.3:
(Fig.3: Industrial Sensor Schematic)
Although a load disconnect function is not included with the new XC9143/44, one can be easily configured externally if required. If VOUT is higher than (VIN + VGS of Pch) then the following circuit will provide the load disconnect function:
(Fig.4: Load Disconnect VOUT)
It is also possible to configure such a function on the input side. If using the open drain of a built-in I/O port of the MCU for this Nch SW, connect the CE of XC9143/44 to the VIN side of CIN (this way is also good for reducing stand-by current):
(Fig.5: Load Disconnect VIN)
The XC9143/44 is also a suitable to drive multiple LEDs in series:
(Fig.6: LED Driver Solution)
The LED current is regulated as:
ILED = VFB / RSENSE (where the VFB = 1.0 V)
so if the ILED is 50 mA, the RSENSE is:
RSENSE = 1.0 V / 50 mA = 20 Ω.
To cut the LED current when the IC is disabled, please add one of load disconnect circuits described in Fig.4 & 5) or add a Nch SW between RSENSE and GND.
The XC9143/44 series is available in TSOT-26 and USP-6C (1.8 x 2.0 x 0.6mm) packages (see Fig.7):
(Fig.7: XC9143/44 Package Line-Up)