7+1 Pwm Mode - Holtek HT45F23A Manual

7+1 PWM Mode

Each full PWM cycle, as it is controlled by an 8-bit PWM register, has 256 clock periods. However,
in the 7+1 PWM mode, each PWM cycle is subdivided into two individual sub-cycles known as
modulation cycle 0 ~ modulation cycle 1, denoted as i in the table. Each one of these two sub-cycles
contains 128 clock cycles. In this mode, a modulation frequency increase of two 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 bit1~bit7 is denoted here as the DC value. The second
group which consists of bit0 is known as the AC value. In the 7+1 PWM mode, the duty cycle value
of each of the two modulation sub-cycles is shown in the following table.
The following diagram illustrates the waveforms associated with the 7+1 mode PWM operation. It
is important to note how the single PWM cycle is subdivided into 2 individual modulation cycles,
numbered 0 and 1 and how the AC value is related to the PWM value.
f / 2
S Y S
[ P W M ] = 1 0 0
P W M
5 0 / 1 2 8
[ P W M ] = 1 0 1
P W M
5 1 / 1 2 8
[ P W M ] = 1 0 2
P W M
5 1 / 1 2 8
[ P W M ] = 1 0 3
P W M
5 2 / 1 2 8
P W M m o d u l a t i o n p e r i o d : 1 2 8 / f
M o d u l a t i o n c y c l e 0
b 7
Rev. 1.40
TinyPower Flash MCU with OPA & Comparators
TM
Parameter AC (0~1)
i<AC
Modulation cycle i
(i=0~1)
i≥AC
7+1 Mode Modulation Cycle Values
5 0 / 1 2 8
5 0 / 1 2 8
5 1 / 1 2 8
5 1 / 1 2 8
S Y S
M o d u l a t i o n c y c l e 1
P W M c y c l e : 2 5 6 / f
S Y S
7+1 PWM Mode
b 0
PWM Register for 7+1 Mode
76
HT45F23A/HT45F24A
DC (Duty Cycle)
DC+1
128
DC
128
M o d u l a t i o n c y c l e 0
P W M R e g i s t e r ( 7 + 1 ) M o d e
A C v a l u e
D C v a l u e
March 29, 2019
5 0 / 1 2 8
5 1 / 1 2 8
5 1 / 1 2 8
5 2 / 1 2 8