Use multiple PCA9552 and control LED blink same frequency

[James_ATLT]

Hi NXP,

We want to use multiple PCA9552 to control more LED, and we think PCA9552 each have an internal clock, so can't sync the blinking frequency between the multiple PCA9552.

And we see the application note "PCA9552_AN264", in the page 20 "Dimming LEDs - Alternative solution using external oscillator", should we use external oscillator to control LED blink same frequency? Or do you have other solution?

Thank you.

[ErikaC]

Hello,

PCA9552 has three hardware address pins on the PCA9552 allow eight devices to operate on the same bus, if you use the external oscillator solution PCA9552 cannot be addressed.

So, how many LEDs you want to use? Please see the FREQUENTLY ASKED QUESTIONS

3. Question: Can the LED Dimmers or Blinkers be used to blink multiple LEDs?
Answer: Each bit is limited to 25 mA, the 8-bit device can provide up to 100 mA total and the 16-bit device can
provide up to 200 mA total (100 mA per 8-bit group). You can put as many LEDs on each bit and package as not to
exceed these limits. Normally there will be one LED on each bit and each LED can be ON, OFF or at Blink Rate 1
or 2. An external FET or a bipolar transistor controlled by the LED blinker output signal can be used to increase the
number of LEDs per output or to pull up the LED supply voltage to some voltage level higher than 6.0 V.

Hope this helps.

[James_ATLT]

Hi ErikaC,

Thanks your reply.
But we use 48 pcs LEDs (3 pcs PCA9552) and if we want to control separately every LEDs, so I think the FREQUENTLY ASKED QUESTIONS 3. still can't solve the questions.

Do you have any other suggestions?

Thank you.

[James_ATLT]

Hi ErikaC,

Sorry, one more question, "alternative solution using external oscillator" just only for dimming LED, not for blinking, is correct?