MLX90805 ETC [List of Unclassifed Manufacturers], MLX90805 Datasheet - Page 7

• Manufacturer Part Number: MLX90805
• Description: Intelligent Triac Controller
• Manufacturer: ETC [List of Unclassifed Manufacturers]

Maximum phase angle
Independent of the phase angle definitions in the
ROM table, a maximum phase angle can be defined.
This is the phase angle that will be applied immedi-
ately after the power on sequence, and is therefore
the first phase angle in the soft start sequence.
This maximum phase angle is defined in MIN[9:0]
with the formula:
With:
Tini = the initial phase angle (in msec)
Fmains = frequency of the mains (in Hz)
Default value:
Tini = 7 msec and Fmains = 50Hz, thus MIN[9:0] is
690.
Soft start time duration
There are 5 bits ATN[4:0] used to define the duration
of the soft start time. The bits can be calculated with
following formula:
With:
Ts = the duration of the soft start (in sec.)
Tini = the initial phase angle defined by MIN[9:0] (in
msec)
Tmin = the phase angle corresponding to the value
in the highest ROM address (in msec)
ATTN = bin2dec(ATN[4:0]+1), a value between 2
and 32.
Default value:
Tini = 8msec, Tmin = 1.84 msec, ATTN = 32, thus Ts
= 3.15 sec.
Firing pulse duration
The duration of the firing pulses can be defined by
the bits DUTS[1:0] according to following table.
The default value is 20 usec.
DUTS1
0
0
1
1
MLX902xx Name of Sensor
MLX90805 Intelligent Triac Controller
MIN[9:0] = Tini * 2 * Fmains - 10
Ts = ((Tini – Tmin) * ATTN ) / 62.5
DUTS0
0
1
0
1
Duration in S
320
80
40
20
Rev Y.X
Page 7
Enable Retriggering
With bit RTRIG set to 1, triac retriggering is enabled.
The retriggering circuit checks whether the triac is
ON, if not additional firing pulses are generated
every 20us (with respect to the end of the previous
firing pulse) until firing of the triac.
With bit RTRIG set to 0, triac retriggering is disabled.
For each triac firing two pulses are generated with a
delay of 20 usec (with respect to the end of the
previous firing pulse).
The default value is triggering enabled.
Retriggering Mask
With the option MINA[3:0] it is possible to define a
zone at the end of each half cycle of the mains
voltage,
retriggering pulses. This has two purposes:
With some (non inductive) loads the current can
become quite small at the end of each half cycle.
This can eventually activate the retriggering circuit
which will unnecessarily generate additional pulses
thus increasing the current consumption.
When generating a retriggering pulse just before the
zero crossing, this pulse could overlap to the next
half period. With some (non inductive) loads this can
lead to false triggering at full power and must be
avoided.
The bits MINA[3:0] are defined according to the
following formula:
Tmina * 2 * Fmains = MINA[3:0] * 64
With:
Tmina = the phase angle from which retriggering is
prohibited (in msec)
Fmains = frequency of the mains (in Hz)
Default value:
MINA[3:0]=1101'b=13'd and Fmain = 50Hz, this
means that retriggering is prohibited at 8.32ms.
Soft start only Function regulator
See page 8
2-wire or 3-wire potentiometer
connection.
See pages 9 and 10
Intelligent Triac Controller
where it
22/Aug/98
is
impossible to
MLX90805
Rev 1.2 17/May/00
generate
Page 7