HT1632
Command
Code
System Oscillator
Name
Function
The HT1632 system clock is used to generate the time
base clock frequency, LED-driving clock. The clock may
be sourced from an on-chip RC oscillator (256kHz), or
an external clock using the S/W setting. The configura-
tion of the system oscillator is as shown. After the SYS
DIS command is executed, the system clock will stop
and the LED duty cycle generator will turn off. This com-
mand is, however, available only for the on-chip RC os-
cillator. Once the system clock stops, the LED display
will become blank, and the time base will also lose its
function. The LED OFF command is used to turn the
LED duty cycle generator off. After the LED duty cycle
generator switches off by issuing the LED OFF com-
mand, using the SYS DIS command reduces power
consumption, serving as a system power down com-
mand. But if the external clock source is chosen as the
system clock, using the SYS DIS command can neither
turn the oscillator off nor execute the power down mode.
The crystal oscillator option can be applied to connect
an external frequency source to the OSC pin. In this
case, the system fails to enter the power down mode,
similar to the case in the external clock source opera-
tion. At the initial system power on, the HT1632 is in the
SYS DIS state.
LED OFF 10000000010X Turn off LED outputs
LED ON
10000000011X Turn on LED outputs
ab=00: N-MOS open
drain output and 8 com-
mon option
ab=01: N-MOS open
drain output and 16
Commons
Option
common option
1000010abXXX
ab=10: P-MOS open
drain output and 8 com-
mon option
ab=11: P-MOS open
drain output and 16
common option
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NMOS Open Drain Driving Mode Configuration
System Oscillator Configuration
LED Driver
LED Color
Red
Current-limiting Resistor
120W at VDD=5V
The HT1632 has a 256 (32´8) and 384 (24´16) pattern
LED driver. It can be configured in a 32´8 or 24´16 pat-
tern and common pad N-MOS open drain output or
P-MOS open drain output LED driver using the S/W
configuration. This feature makes the HT1632 suitable
for multiple LED applications. The LED-driving clock is
derived from the system clock. The driving clock fre-
quency is always 256kHz, an on-chip RC oscillator fre-
quency, or an external frequency. The LED
corresponding commands are summarized in the table.
The bold form of 1 0 0, namely 1 0 0, indicates the com-
mand mode ID. If successive commands have been is-
sued, the command mode ID except for the first
command will be omitted. The LED OFF command turns
the LED display off by disabling the LED duty cycle gen-
erator. The LED ON command, on the other hand, turns
the LED display on by enabling the LED duty cycle gen-
erator.
Green
100W at VDD=5V
Recommended Current-limiting Resistor for NMOS
Open Drain Driving Mode
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PMOS Open Drain Driving Mode Configuration
Rev. 1.30
7
June 28, 2011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
