Datasheet

NCP5612
http://onsemi.com
8
• The first four positive going pulses are used to control
the ICON (LED2):
1. Pulse #1 ³ ICON = 100 mA
2. Pulse #2 ³ ICON = 150 mA
3. Pulse #3 ³ ICON = 250 mA
4. Pulse #4 ³ ICON = 450 mA
• The fifth positive pulse will clear the ICON and
activate the normal operation of LED1 and LED2
• The pulses from the fifth to the twentieth will increase
the LED current according to a pseudo logarithmic
scale (see Figure 9).
• Any pulses beyond the twentieth will not make change
to the LED current if the delay between the pulses is
shorter than 75 ms.
• The system returns to zero if a pulse, delayed by
200Ăms – T
dst
– , follows the twentieth one and the
cycle restart from the beginning.
Once the expected LED current value is reached, the
CNTL pin must stay High to store the new data and
maintain the LED active.
The contain of the counter is stored into the internal LED
registers at the end of the built−in 200 ms typical delay: no
action will take place during the end of the last positive
going pulse and the end of the T
dst
delay. Such a protocol
prevent the system for broken transmission.
On the other hand, in order to avoid corrupted data
transmission, the High level shall be 75 ms maximum
during a given data frame. Consequently, the pulse
frequency is bounded by a 13 kHz minimum and a 400 kHz
maximum.
Figure 8. Basic NCP5612 Programming Sequence
Example #1: CNTL
LED1= 0 mA
Example #2: CNTL
1 23
Start Bit
Negative going edge
Shut down mode
Clear counter
LED1=LED0= 0 mA
LED2 = ICON
LED1= 6 mA
LED2 = 6 mA
LED1=LED2 = 6 mA
Pulse count
Pulse count
Example #3: CNTL
1234
5 6789
LED1= 30 mA
LED2 = 30 mA
10
ICON = disabled
LED1=LED2 = 30 mA
Pulse count
11 12 13 14 15 16 17 18 19 20
LED1=LED2 = 0 mA
Note: timings are not scaled.
T
dst
1234 5 678910
T
dst
ICON = disabled
T
EH
ICON = 250 mA
T
EH
max 75 ms when clocked
T
dst
T
EL