Renesas’ announcement this week of its ultra-low-power RL78/L1C got my attention, but I stopped short of doing a teardown of my son’s somewhat bulky blood glucose meter. With the PCB taking up much of its height, it could be downsized considerably while still retaining a large LCD screen if the components were better integrated. Better battery life would be a plus, too. The RL78/L1C was designed to deliver both for portable medical and healthcare applications.
With up to 16 KB of RAM and 256 KB of flash memory the RL78/L1C integrates an LCD controller, 12-bit ADC, and USB 2.0 functionality in low-profile RL78 package. The 24 MHz/33 DMIPS MCU can work off a CR2032 coin cell for a long time, drawing 112.5 μA/MHz in Run mode and 0.62 μA in Stop mode (RTC + LCD). The USB module can detect a battery charging connection during function controller operation compliant to Battery Charging Specification Revision 1.2, which enables high-speed battery charging up to 1.5A.
The RL78/L1C can work with a wide range of sensors, needing only the appropriate sensor module to comprise a complete solution for portable medical and healthcare devices, industrial metering and measurement equipment, home appliances, and consumer electronics. An on-chip temperature sensor can be selected as one of the 13 analog input channels. The analog chain consists of the 12-bit ADC, two independent comparators, and a two-channel 8-bit DAC.
The LCD controller can drive a 52-segment (X 8 com) or 56-segment (x 4 com) display. The LCD driver voltage generator can switch using either an internal voltage boosting method, capacitor split method, or external resistance division method. While driving the LCD the RL78/L1C draws 30 percent less current than previous generation (R8C) devices.
For more information check out the RL78/L1C datasheet and Hardware User’s Manual.