TC646EUA713 Microchip Technology, TC646EUA713 Datasheet - Page 8

• Manufacturer Part Number: TC646EUA713
• Description: IC PWM FAN SPEED CONTRLR 8-MSOP
• Manufacturer: Microchip Technology
• Type: Controller - PWM Fanr

Specifications of TC646EUA713

• Applications: Fan Controller, Brushless (BLDC)
• Number Of Outputs: 1
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Product: Fan / Motor Controllers / Drivers
• Operating Supply Voltage: 3 V to 5.5 V
• Supply Current: 1 mA
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Load: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

TC646
4.0
The flowcharts describing the TC646’s behavioral
algorithm are shown in Figure 4-1. They can be
summarized as follows:
4.1
(1) Assuming the device is not being held in auto-shut-
(2) Turn V
(3) During this Start-up Timer, if a fan pulse is
(4) Activate the 32-cycle Start-up Timer one more time
(5) Proceed to Fan Fault.
(6) End.
4.2
“Normal Operation” is an endless loop which may only
be exited by entering shutdown mode, auto-shutdown
mode or Fan Fault. The loop can be thought of as
executing at the frequency of the oscillator and PWM.
(1) Reset the missing pulse detector.
(2) Is the TC646 in shutdown or auto-shutdown
(3) If an over-temperature fault occurs (V
(4) Drive V
(5) If a fan pulse is detected, branch back to the
(6) If the missing pulse detector times out …
(7) Activate the 3-cycle Diagnostic Timer and look
(8) Activate the 32-cycle Start-up Timer and look for
(9) Quit Normal Operation and go to Fan Fault.
(10) End.
DS21446C-page 8
down mode (V
clock. This ensures that the fan will start from a
dead stop.
detected, branch to Normal Operation; if none are
received…
and look for fan pulse; if a fan pulse is detected,
proceed to Normal Operation; if none are
received…
mode?
If so...
a. V
b. FAULT is disabled.
c. Exit the loop and wait for V
activate FAULT; release FAULT when
V
a cycle by cycle basis.
start of the loop (1).
for pulses; if a fan pulse is detected, branch
back to the start of the loop (1); if none are
received…
pulses; if a fan pulse is detected, branch back to
the start of the loop (1); if none are received…
IN
resume operation.
< V
OUT
SYSTEM BEHAVIOR
Power-Up
Normal Operation
OTF
OUT
OUT
duty cycle goes to zero.
.
output on for 32 cycles of the PWM
to a duty cycle proportional to V
IN
> V
AS
)..........
IN
> (V
AS
IN
+ V
> V
OTF
HAS
IN
on
),
) to
4.3
Fan fault is an infinite loop wherein the TC646 is
latched in shutdown mode. This mode can only be
released by a reset (i.e., V
V
(1) While in this state, FAULT is latched on (low) and
(2) A reset sequence applied to the V
(3) End.
SHDN
the V
loop to Power-up.
, then above (V
Fan Fault
OUT
output is disabled.
AS
+ V
2002 Microchip Technology Inc.
HAS
IN
), or by power-cycling).
being brought below
IN
pin will exit the