HT46R064D/065D/066D
Enhanced A/D Type 8-Bit OTP MCU with LED Driver
6+2 PWM Mode
Each full PWM cycle, as it is controlled by an 8-bit PWM register, has 256 clock periods. However, in
the 6+2 PWM mode, each PWM cycle is subdivided into four individual sub-cycles known as
modulation cycle 0 ~ modulation cycle 3, denoted as i in the table. Each one of these four sub-cycles
contains 64 clock cycles. In this mode, a modulation frequency increase of four is achieved. The 8-bit
PWM register value, which represents the overall duty cycle of the PWM waveform, is divided into
two groups. The first group which consists of bit2~bit7 is denoted here as the DC value. The second
group which consists of bit0~bit1 is known as the AC value. In the 6+2 PWM mode, the duty cycle
value of each of the four modulation sub-cycles is shown in the following table.
Parameter
AC (0~3)
DC (Duty Cycle)
DC+1
64
i<AC
Modulation cycle i
(i=0~3)
DC
64
i³AC
6+2 Mode Modulation Cycle Values
The following diagram illustrates the waveforms associated with the 6+2 mode of PWM operation.
It is important to note how the single PWM cycle is subdivided into 4 individual modulation cycles,
numbered from 0~3 and how the AC value is related to the PWM value.
6+2 PWM Mode
PWM Register for 6+2 Mode
Rev. 1.00
54
January 12, 2011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
