Problem with TLC59283, 16 Channel Constant Current LED Driver with Pre-Charge FET.
Schematic diagram: similar to Typical application Circuit in the datasheet. 3x TLC59283 for 6 LED matrices 5x7, multiplexed LEDS.
So 5 columns that go to all te matrices.
V-LED is 3.5V.
Voltage constant-current outputs: 2V if not active (no current through LED), 1.5V when active (current through the LED).
R-IREF 5k6, so output current 9 - 10 mA.
When one TLC59283 has many constant-current outputs active, for example 2x7 (2 columns, 7 rows), there is no problem.
When 2 or more TLC59283’s have many constant-current outputs active, and they do that in the same columns, then constant-current outputs that column is active seems to oscillate.
For example IIIIII or HHHHHH or LLLLLL on displays: each TLC59283 has 2x7 outputs active (2 columns, 7 rows).
Oscillation frequency approx. 19 to 25 MHz, seems to vary with V-LED, or probably the Voltage on the constant-current outputs, because that depends on V-LED.
Question: is this a known phenomenon, is there something we can/should do to prevent this ?