STEVAL-ISA033V1 STMicroelectronics, STEVAL-ISA033V1 Datasheet - Page 13

• Manufacturer Part Number: STEVAL-ISA033V1
• Description: BOARD EVAL L5991/STP12NK80Z
• Manufacturer: STMicroelectronics
• Type: Supervisory Circuitsr

Specifications of STEVAL-ISA033V1

• Main Purpose: AC/DC, Primary Side
• Outputs And Type: 3, Isolated
• Power - Output: 55W
• Voltage - Output: 13.8V, 3.8V, 25V
• Current - Output: 3A, 350mA, 200mA
• Voltage - Input: 88 ~ 300VAC
• Regulator Topology: Flyback
• Board Type: Fully Populated
• Utilized Ic / Part: L5991, STP12NK80Z
• Input Voltage: 88 V to 300 V
• Output Voltage: 3.8 V to 25 V
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: L5991, STP12NK80Z
• Other names: 497-8226; STEVAL-ISA033V1

Figure 30. Disable (Latched).
connecting DC-LIM to VREF (half duty cycle op-
tion), Dx will be set approximately at:
Figure 31. Half duty cycle option.
Figure 32. Standby function internal schematic and operation.
DISABLE
SIGNAL
C
FB
DIS
5
2.5
D
x
+
-
14
2.5V
2 R
COMP
6
V15=GND
V5=V13=GND
V15=VREF
V5=V13=GND
+
-
R
T
2.5/4
T
260
STANDBY BLOCK
t c
t c
+
-
2R
R
13
11
ISEN
UVLO
LEVEL SHIFT
D
R
+
-
10V
Q
DISABLE
STANDBY
D97IN502
t
d
t
d
R
DRIVER
and the output switching frequency will be halved
with respect to the oscillator one because an in-
ternal T flip-flop (see block diagram) is activated.
Fig. 31 shows the operation.
The half duty cycle option speeds up the dis-
charge of the timing capacitor C
duty cycles as close to 50% as possible) so the
oscillator frequency - with the same timing compo-
nents will be slightly higher.
Pin 16. S-BY (Standby Function). The resistor R
along with R
oscillator in normal operation (f
as the STANDBY signal is high, the pin is inter-
nally connected to the reference voltage VREF by
a N-channel FET (see fig. 32), so the timing ca-
pacitor C
the STANDBY signal goes low the N-channel FET
is turned off and the pin becomes floating. R
D97IN498
16
4
2
OUT
VREF
ST-BY
RCT
R
B
T
is charged through R
V10
V10
V2
V2
A
R
C
A
, sets the operating frequency of the
T
STANDBY
HIGH
LOW
D
D
X
X
D97IN752B
=
=
2 ·t c + t d
t c + t d
t c
t c
2.5V
V
T1
osc
L5991 - L5991A
V
4V
T2
T
A
). In fact, as long
(in order to get
and R
V
COMP
B
. When
13/23
B
B
is
,