EMC2301-1-ACZL-TR 参数 Datasheet PDF下载

RPM-Based PWM Fan Controller

Datasheet

Chapter 4 Product Description

The EMC2301 is an SMBus compliant fan controller with a programmable frequency PWM fan driver.

The fan driver can be operated using two modes: the RPM-based Fan Speed Control Algorithm or the

direct fan drive setting.

shows a system diagram of the EMC2301.

3.3V

VDD

SMCLK

TACH

PWM

ALERT#

tachometer

MCU

SMDATA

Drive

Circuit

32.768KHz Clock

Input or Output

CLK

GND

EMC2301

Figure 4.1 System Diagram of EMC2301

4.1

Fan Control Modes of Operation

The EMC2301 has two modes of operation for the fan driver. Each mode of operation uses the Ramp

Rate control and Spin Up Routine.

1. Direct Setting Mode - in this mode of operation, the user directly controls the fan drive setting.

Updating the Fan Driver Setting Register (see

will instantly update the PWM fan drive.

Ramp Rate control is optional and enabled via the EN_RRC bits.

Whenever the Direct Setting Mode is enabled, the current drive will be changed to what was

last written into the Fan Driver Setting Register.

2. Fan Speed Control Mode (FSC) - in this mode of operation, the user determines a target

tachometer count and the PWM drive setting is automatically updated to achieve this target speed.

The algorithm uses the Spin Up Routine and has user definable ramp rate controls.

This mode is enabled setting the EN_ALGO bit in the Fan Configuration Register.

Table 4.1 Fan Controls Active for Operating Mode

DIRECT SETTING MODE

Fan Driver Setting (read / write)

EDGES[1:0]

FSC MODE

Fan Driver Setting (read only)

EDGES[1:0]

(Fan Configuration)

Revision 1.1 (10-12-09)

16

SMSC EMC2301

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