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12-07-0006 PT0261-1 07/06/12
4
PT8A3280/1/2/3/4/5/6/7
Heating Controller
Functional Description
State description
Reset
The device will be of reset state after power-on.
Heating on
The device will be heating on after power on.
Heating off
This device enter heating-off state after its power-on reset or heating timer timeout, and all pins will be the same status as after
power-on reset.
NTC open protection
When NTC is open, NTC1 pin will be pulled low in the period of NTC open detected.
Timer
Once IC enters Heating-on State, internal timer starts to count. When time is out after 216000 clock period, it will exit heating-on
state. That is, in case of 60Hz CLK signal, the heating time is about 1 hour; and 1.2 hour for 50Hz.
In heating-on state, temperature is regulated to the selected temperature by the IC through NTC close control loop.
Control signal output
When working in Heating-on state, Gate/LED output will be related to NTC1 input and CLK input amplitude.
Effect of NTC and VT
CLK
(Level 2) on GATE and LED indication
NTC
(Normal temp
detection)
GATE
(trigger to
SCR/TRIAC)
*Note: 1) X means any input. 2) Flash1 frequency is 1/32 clock. 3) Flash2 frequency is 1/8 clock
