EMC6D103-CZC SMSC, EMC6D103-CZC Datasheet - Page 40

• Manufacturer Part Number: EMC6D103-CZC
• Description: Industrial Temperature Sensors Auto Fan Contrllr Up to 4 Fans
• Manufacturer: SMSC

Specifications of EMC6D103-CZC

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Revision 0.3 (03-01-07)
Ramping Duty Cycle
Calculate Duty Cycle
PWM Duty Cycle
Ramping Duty Cycle
Calculate Duty Cycle
PWM Duty Cycle
RRX-
[2:0]
Example 1: PWM period < Ramp Rate Step Size
PWM frequency = 87.7Hz (11.4msec) & PWM Ramp Rate = 38.46Hz (26msec)
Example 2: PWM period > Ramp Rate Step Size
PWM frequency = 11Hz (90.9msec) & PWM Ramp Rate = 38.46Hz (26msec)
100
101
110
111
Notes:
It should be noted that the actual duty cycle on the pin is created by the PWM Ramp Rate Control
block and latched on the rising edge of the PWM output. Therefore, the current PWM duty cycle may
lag the PWM Calculated Duty Cycle.
PWM RAMP TIME (SEC)
100% DUTY CYCLE)
The PWM Duty Cycle latches the Ramping Duty Cycle on the rising edge of the PWM output.
The calculated duty cycle, ramping duty cycle, and the PWM output duty cycle are asynchronous
to each other, but are all synchronized to the internal 90kHz clock source.
(TIME FROM 33%
DUTY CYCLE TO
4.4
3.0
1.6
0.8
70h
70h
70h
70h
70h
70h
Figure 7.4 Illustration of PWM Ramp Rate Control
Fan Control Device with High Frequency PWM Support and Hardware Monitoring Features
Table 7.1 PWM Ramp Rate (continued)
11.4ms
71h
71h
71h
PWM RAMP TIME (SEC)
26ms
26ms
CYCLE TO 100% DUTY
(TIME FROM 0% DUTY
71h
DATASHEET
11.4ms
CYCLE)
71h
1.275
6.63
4.59
2.55
74h
74h
40
11.4ms
72h
72h
72h
26ms
26ms
71h
90.9msec
11.4ms
72h
11.4ms
73h
(PWM STEP SIZE =
PWM STEP
TIME PER
73h
73h
26 msec
18 msec
10 msec
11.4ms
73h
5 msec
1/255)
11.4ms
73h
74h
11.4ms
74h
74h
SMSC EMC6D103
74h
11.4ms
RAMP
RATE
PWM
38.46
55.56
74h
100
200
(HZ)
Datasheet
74h