MC33364D ON Semiconductor, MC33364D Datasheet - Page 7

• Manufacturer Part Number: MC33364D
• Description: IC CTRLR SMPS OTP UVLO 16SOIC
• Manufacturer: ON Semiconductor
• Series: GreenLine™r

Specifications of MC33364D

• Output Isolation: Isolated
• Frequency Range: 104 ~ 800kHz
• Voltage - Input: 7.6 ~ 16 V
• Voltage - Output: 700V
• Power (watts): 550mW
• Operating Temperature: -25°C ~ 150°C
• Package / Case: 16-SOIC (0.154", 3.90mm Width) 14 leads
• Number Of Outputs: 1
• Output Voltage: 4.90 V to 5.20 V
• Output Current: 600 mA
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 16 V
• Maximum Operating Temperature: + 125 C
• Fall Time: 28 ns
• Minimum Operating Temperature: - 25 C
• Rise Time: 67 ns
• Synchronous Pin: No
• Topology: Flyback
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: MC33364DOS

Introduction
current- -mode critical- -conduction solution with integrated
high voltage startup and protection circuitry to implement an
off- -line flyback converter for modern consumer electronic
power supplies. Different frequency clamp options offer
different customized needs. This device series includes an
integrated 700 V Very High- -Voltage (VHV) start- -up
circuit. Thus, it is possible to design an application with
universal input voltage from 85 Vac to 265 Vac without any
additional startup circuits or components.
First, the MOSFET turns on at zero current and the diode
turns off at zero current. The zero current reduces these
turn- -on and turn- -off switching losses. It also reduces the
Electro- -Magnetic Interface (EMI) of the SMPS and a less
expensive rectifier can be used. Second, by preventing the
SMPS from entering the discontinuous conduction mode
(DCM), the peak MOSFET drain current is limited to only
twice the average input current. It needs a smaller and less
expensive MOSFET. Third, by preventing the SMPS from
entering the Continuous Conduction Mode (CCM), the
flyback topology transfer function stays first- -order and its
feedback compensation network is considerably simplified.
It also maximizes the power transfer by the flyback
transformer to its 1/2 L I
below. The representative block diagram and typical
application circuit are in Figure 1 and Figure 2.
Line, V
possible to connect this pin directly to the rectified
high- -voltage Alternating Current (AC)
minimizing the number of external components. There is a
startup circuit block that regulates voltage from the Line pin
to the V
conditions, the auxiliary winding powers up the V
this startup circuit is opened and saves approximate 0.7 W
of power compared to the resistor bootstrapped circuits.
V
UVLO limits (7.6 V and 15 V). It is further regulated to a
constant 5 V reference voltage V
usage. As long as the V
15 V, it means the auxiliary winding can provide voltage as
in normal condition. The device recognizes that there is no
fault in the circuit and the device remains in the normal
operation status.
V
recognizes that it is an abnormal situation (such as startup or
output short- -circuited). The V
CC
CC
The MC33364 series represents a variable- -frequency
The critical conduction feature offers some advantages.
A description of each of the functional blocks is given
The Line pin is capable of a maximum 700 V so that it is
In normal operation, the auxiliary winding powers up the
However, when the auxiliary winding cannot power up
, the V
voltage. This voltage is a constant value between the
CC
CC
, Startup Circuit and Reference Voltage
CC
voltage will reach its UVLO limit. The device
pin in an abnormal situation. In normal
2
CC
limits.
voltage is between 7.6 V and
CC
ref
voltage is not constant in
for the internal circuitry
OPERATING DESCRIPTION
input for
CC
http://onsemi.com
and
7
this case. Figure 3 shows the timing diagram in a fault
condition. There are three Under- -Voltage Lock- -Out
(UVLO) thresholds with respect to V
threshold is 15 V. When this limit is reached, the startup
circuit block turns off and V
consumption of the circuitry. The startup circuit block turns
on when V
It is the second threshold of V
3.7 V, the startup circuit will turn on when V
temperature dependent value V
6 V. It is the last threshold of V
dependent threshold is lower when temperature is higher so
that it takes a longer time to restore the V
feature, which allows more dead time for cooling in high
temperature condition.
falls below typical 8.1 V in abnormal situation, the V
regulator block stops. V
consumption of the circuitry. When V
3.7 V, the device cannot provide the Drive output and makes
a dead time. This dead time is designed for minimal power
transfer in the abnormal conditions. The dead time ends
when V
(3.5 to 6 V). Reaching V
charging up the V
15 V again, the V
output to work again.
stability of the voltage buffer. The V
relatively larger than this 0.1 uF capacitor, making a longer
V
in the abnormal or fault conditions.
Zero Current Detect
conduction is always initiated by sensing a zero current
signal from the Zero Current Detect (ZCD) pin. The ZCD
pin indirectly monitors the inductor current by sensing the
auxiliary winding voltage. When the voltage falls below a
threshold of 1.0V, the comparator resets the RS latch to turn
the MOSFET on. There is 200 mV of hysteresis built into the
comparator for noise immunity and to prevent false tripping.
There are 10 V and 0.7 V clamps in the ZCD pin for
protection. An external resistor is recommended to limit the
input current to 2 mA to protect the clamps.
Watchdog Timer
restart the Drive output when something goes wrong in the
ZCD. When the inductor current reaches zero for longer than
approximate 410 ms, the timer reset the RS latch and that
turns the MOSFET on.
CC
There is an UVLO in the V
It is recommended to put a 0.1 uF capacitor on V
To achieve critical conduction mode, MOSFET
A watchdog timer block is added to the device to start or
charging time from V
CC
CC
reaches 15 V after reaching the UVLO limit V
reaches 7.6 V and if V
ref
CC
regulator block turns on and allows the
capacitor again. When V
ref
T
enables the startup circuit block,
and V
T
to 15 V and a longer dead time
ref
T
CC
regulator block. When V
CC
ranging between 3.5 V and
CC
. If V
declines due to power
collapses due to power
ref
CC
ref
is higher than 3.7 V.
. This temperature
CC
collapses to below
ref
. It is a protection
CC
CC
is smaller than
. The upper
CC
capacitor is
CC
reaches a
ref
reaches
pin for
CC
ref
T