Typical application circuit of CP2131

MP24AE off-the-shelf supply

AVX tantalum capacitor TAJB106K016RNJ stock

CP2131 is a parallel white LED driver chip, which can adaptively select 1x voltage or 1.5x voltage working mode according to the power supply voltage and the on-voltage drop of white LED to ensure the chip is within the working voltage range of the whole lithium ion battery. High efficiency. The new Auto-Mirror technology makes the current matching of each parallel white LED almost unchanged with the difference in white LED turn-on voltage drop. In a typical case, the white LED can have a current matching of up to 0.5%. The use of CP2131 to form a white LED driver circuit requires only four ceramic capacitors, making it ideal for battery power applications in portable electronic devices. The CP2131 adopts the PWM dimming mode of the non-shutdown mode to set the brightness of the white LED, and the dimming rate can be as high as 50 kHz. At the same time in the startup and dimming modes, the CP2131 is able to guarantee relatively small input current fluctuations and low EMI. The CP2131 has a shutdown mode with a shutdown current of less than 0.1 microamps. The main technical features of the CP2131 are as follows.
1 drives up to 3 LEDs, each with a maximum current of 30mA.
2 Current matching accuracy is 0.5% (typical).
3Auto-Mirror technology is adopted to ensure the current matching degree is improved when the parallel voltage difference of each parallel white LED is large.
4 High efficiency 1x and 1.5x mode can be adaptively switched according to input voltage and load, with an efficiency of up to 90%.
5 support PWM (frequency range is 0 ~ 50kHz) brightness adjustment mode.
6 small input current fluctuations and low EMI.
7 No external inductance is required.
8 switching frequency is 1MHz.
9 with overcurrent protection and overheat protection.
10 operating voltage range of 2.7 ~ 5.5V, using a small 3 ∏ m × 3mrn QFN 1 6L package.
For the efficiency problem of concern, CP2130, CP2131 and CP2133 realize adaptive dynamic switching of two working modes (ie according to battery voltage and LED actual conduction voltage drop) instead of fixed voltage point switching (ie only considering battery voltage), It is possible to operate the charge pump in the 1x mode, which significantly increases the efficiency.