M51995AFP MITSUBISHI, M51995AFP Datasheet

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M51995AFP

Manufacturer Part Number
M51995AFP
Description
IC REG STEP DOWN SWITCH ADJ POS 1.4V TO 16V 2A 20SOP
Manufacturer
MITSUBISHI
Datasheet
DESCRIPTION
M51995A is the primary switching regulator controller which is
especially designed to get the regulated DC voltage from AC power
supply.
This IC can directly drive the MOS-FET with fast rise and fast fall
output pulse.
Type M51995A has the functions of not only high frequency OSC
and fast output drive but also current limit with fast response and
high sensibility so the true "fast switching regulator" can be
realized.
It has another big feature of current protection to short and over
current,owing to the integrated timer-type protection circuit,if few
parts are added to the primary side.
The M51995A is equivalent to the M51977 with externally re-
settable OVP(over voltage protection)circuit.
FEATURES
APPLICATION
Feed forward regulator,fly-back regulator
RECOMMENDED OPERATING CONDITIONS
Supply voltage range............................................12 to 36V
Operating frequency.................................less than 500kHz
Oscillator frequency setting resistance
•Output current...............................................................±2A
•Output rise time 60ns,fall time 40ns
•Modified totempole output method with small through current
•Small start-up current............................................90µA typ.
•Big difference between "start-up voltage" and "stop voltage"
•Packages with high power dissipation are used to with-stand the
•High-speed current limiting circuit using pulse-by-pulse
•Protection by intermittent operation of output over current......
•Over-voltage protection circuit with an externally re-settable
•Protection circuit for output miss action at low supply
•Triangular wave oscillator for easy dead time setting
makes the smoothing capacitor of the power input section small.
..........................................................Timer protection circuit
latch(OVP)
voltage(UVLO)
High-performance and highly functional power supply
Compact and light-weight power supply
Start-up threshold 16V,stop voltage 10V
500kHz operation to MOS FET
heat generated by the gate-drive current of MOS FET.
16-pin DIP,20-pin SOP 1.5W(at 25°C)
Simplified peripheral circuit with protection circuit and built-in
large-capacity totempole output
method(Two system of CLM+pin,CLM-pin)
•T-ON pin resistance R
•T-OFF pin resistance R
ON
OFF
...........................10k to 75k
..........................2k to 30k
(
1
/ 27 )
PIN CONFIGURATION (TOP VIEW)
HEAT SINK PIN
COLLECTOR
COLLECTOR
EMITTER
EMITTER
SWITCHING REGULATOR CONTROL
ON/OFF
ON/OFF
MITSUBISHI (Dig./Ana. INTERFACE)
V
V
DET
DET
OVP
OVP
OUT
F/B
OUT
F/B
VF
VF
10
Outline 20P2N-A
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
9
Outline 16P4
Connect the heat sink pin to GND.
M51995AP/FP
16
15
14
13
12
11
10
20
19
18
17
16
15
14
13
12
11
9
Vcc
CLM+
CLM-
GND
CT
T-OFF
CF
T-ON
Vcc
CLM+
CLM-
GND
CT
T-OFF
CF
T-ON
HEAT SINK PIN

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M51995AFP Summary of contents

Page 1

... Supply voltage range............................................12 to 36V Operating frequency.................................less than 500kHz Oscillator frequency setting resistance •T-ON pin resistance R ...........................10k to 75k ON •T-OFF pin resistance R ..........................2k to 30k OFF MITSUBISHI (Dig./Ana. INTERFACE) SWITCHING REGULATOR CONTROL PIN CONFIGURATION (TOP VIEW) COLLECTOR 1 V OUT 2 EMITTER ...

Page 2

BLOCK DIAGRAM V CC UNDER ON/OFF VOLTAGE LOCKOUT OVP(shut down) LATCH OSCILLATOR CAPACITANCE CF OSCILLATOR OSCILLATOR RESISTANCE T-ON (ON duty) (TRIANGLE) OSCILLATOR RESISTANCE T-OFF (OFF duty) VF ABSOLUTE MAXIMUM RATINGS Symbol Parameter V Supply voltage CC V Collector voltage C ...

Page 3

ELECTRICAL CHARACTERISTICS Symbol Parameter Block V Operating supply voltage range CC V Operation start up voltage CC(START) V Operation stop voltage CC(STOP) Difference voltage between Vcc operation start and stop Stand-by current Icc L Operating circuit current Icc O Circuit ...

Page 4

ELECTRICAL CHARACTERISTICS Symbol Parameter Block Oscillating frequency f OSC T Maximum ON duty DUTY Upper limit voltage of oscillation waveform V OSCH V Lower limit voltage of oscillation waveform OSCL Voltage difference between upper limit and V OSC lower limit ...

Page 5

TYPICAL CHARACTERISTICS THERMAL DERATING (MAXIMUM RATING) 1800 1500 1200 900 600 300 100 AMBIENT TEMPERATURE Ta(°C) CIRCUIT CURRENT VS.SUPPLY VOLTAGE (OVP OPERATION) 8.0 OVP RESET POINT 8.87V(-30°C) 7.0 8.94V(25°C) 9.23V(85°C) 6.0 5.0 Ta=-30°C 4.0 ...

Page 6

THRESHOLD VOLTAGE OF ON/OFF TERMINAL VS.AMBIENT TEMPERATURE 3.4 3.2 3.0 ON OFF 2.8 2.6 2.4 OFF ON 2.2 2.0 1.8 -40 - AMBIENT TEMPERATURE Ta(°C) INPUT CURRENT OF VF TERMINAL VS.INPUT VOLTAGE - ...

Page 7

VF THRESHOLD VOLTAGE FOR TIMER VS. AMBIENT TEMPERATURE 3.5 3.0 2.5 -40 - -60 AMBIENT TEMPERATURE Ta(°C) THRESHOLD VOLTAGE OF CLM- TERMINAL VS. AMBIENT TEMPERATURE 205 200 195 -40 - -60 AMBIENT TEMPERATURE Ta(°C) ...

Page 8

OUTPUT LOW VOLTAGE VS. OUTPUT SINK CURRENT 5.0 Ta=25°C 4.0 3.0 Vcc=18V 2.0 Vcc=5V 1.0 0 10m 100m 1m OUTPUT SINK CURRENT I INPUT CURRENT OF DETECTION AMP VS. AMBIENT TEMPERATURE 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 ...

Page 9

ON duty VS. F/B TERMINAL INPUT CURRENT Ta=-30°C Ta=25°C Ta=85° 0.5 1.0 1.5 F/B TERMINAL INPUT CURRENT I OSCILLATING FREQUENCY VS. CF TERMINAL CAPACITY 10000 1000 R =22k ON R ...

Page 10

ON duty VS. AMBIENT TEMPERATURE 100 (f =100kHz) OSC -60 -40 - AMBIENT TEMPERATURE Ta(°C) ON duty VS. AMBIENT TEMPERATURE 100 (f =500kHz) OSC ...

Page 11

CURRENT FROM OVP TERMINAL FOR OVP RESET VS. SUPPLY VOLTAGE 800 700 600 500 Ta=-30°C Ta=25°C 400 Ta=85°C 300 200 100 SUPPLY VOLTAGE Vcc( M51995AP/FP ...

Page 12

... FUNCTION DESCRIPTION Type M51995AP and M51995AFP are especially designed for off-line primary PWM control IC of switching mode power supply (SMPS) to get DC voltage from AC power supply. Using this IC,smart SMPS can be realized with reasonable cost and compact size as the number of external electric ...

Page 13

... The cycle time of oscillation is given by the summation of Equations 2 and 4. The frequency including the dead-time is not influenced by the temperature because of the built-in temperature compensating circuit MITSUBISHI (Dig./Ana. INTERFACE) M51995AP/FP SWITCHING REGULATOR CONTROL current and one OFF current by the function of Q2,Q3 and ...

Page 14

OSC control circuit operates. When over current signal is applied to CLM+ or CLM- terminal,and the current limiting circuit,intermittent action and OSC control circuit starts to operate.In this case T-OFF terminal voltage depends on ...

Page 15

PWM comparator and PWM latch section Fig.9 shows the PWM comparator and latch section. The on- duration of output waveform coincides with the rising duration of CF terminal waveform,when the infinitive resistor is connected between F/B terminal and GND. When ...

Page 16

It is rather recommended to use not "CLM+" but "CLM-" terminal,as the influence from the gate drive current of MOS-FIT can be eliminated and wide voltage rating -4V is guaranteed for absolute maximum rating. There happen ...

Page 17

NO OPERATING DURATION 2V Fig.15 Waveform of CT terminal Fig.16 shows the Icc versus Vcc in this timer-off duration. In this duration the power is not supplied to IC from the third winding of transformer but through from the resistor ...

Page 18

Fig.20 shows how to connect the ON/OFF terminal.The switching operation will stop by swich-off and operate by switch- on. Transistor or photo transistor can be replaced by this switch,of course.No resistor 100k is connected and ON/OFF terminal ...

Page 19

Vcc 7.8V 8k 12k Q1 Q2 400 OVP 2. GND I1=0 when OVP operates Fig.22 Detail diagram of OVP circuit 8 OVP RESET POINT 8.82V(-30°C) 7 8.97V(25°C) 9.07V(85° Ta=-30°C Ta=25°C 4 Ta=85° ...

Page 20

It is not necessary that the induced voltage is settled higher than the operation start-up voltage Vcc drive voltage causes high gate dissipation,on the other hand,too low gate drive voltage does not make the MOS-FET fully on- state or the ...

Page 21

Vcc M51995A CVcc1 GND Fig.27 DC source circuit for stable start-up OVP circuit (1)To avoid the miss operation of OVP It is recommended to connect the capacitor between OVP terminal and GND for avoiding the miss operation by the spike ...

Page 22

Current limiting circuit (1)Peripheral circuit of CLM+,CLM- terminal Fig.31 and 32 show the example circuit diagrams around the CLM+ and CLM- terminal.It is required to connect the low pass filter,as the main current or drain current contains the spike current ...

Page 23

Under the condition of current limiting operation,the output current I2 continues as shown in Fig.33.So the output voltage depends on the product of the input primary voltage V on-duty. If the third winding polarity is positive ,the Vcc depends on ...

Page 24

... To use the buffer circuit shown next section (3)Output buffer circuit It is recommended to use the output buffer circuit as shown in Fig.42,when type M51995A drives the large capacitive load or bipolar transistor. as the GS affect to the ( / MITSUBISHI (Dig./Ana. INTERFACE) M51995AP/FP SWITCHING REGULATOR CONTROL V =80V DS V =200V DS V =320V ...

Page 25

V OUT M51995A Fig.42 Output buffer circuit diagram DET Fig.43 shows how to use the DET circuit for the voltage detector and error amplifier. For the phase shift compensation,it is recommended to connected the CR network between det terminal and ...

Page 26

Vcc Vcc M51995A -Vss GND (-2V to -5V) Fig.47 Driver circuit diagram (1) for bipolar transistor Driver circuit for bipolar transistor When the bipolar transistor is used instead of MOS-FIT,the base current of bipolar transistor must be sinked by the ...

Page 27

... APPLICATION EXAMPLE Feed forward types SMPS with multi-output FIN V OUT VF SWITCHING REGULATOR CONTROL R1 COLLECTOR Vcc M51995AP ON/OFF OFF MITSUBISHI (Dig./Ana. INTERFACE) M51995AP/ Cvcc OVP F/B V OUT2 V OUT1 ON/OFF ...

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