M51996FP MITSUBISHI, M51996FP Datasheet

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M51996FP

Manufacturer Part Number
M51996FP
Description
Switching regulator control
Manufacturer
MITSUBISHI
Datasheet
DESCRIPTION
M51996A 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 and with a large-drive totempole output.
Type M51996A 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.
The M51996A is equivalent to the M51978 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 30V
Operating frequency.................................less than 500kHz
Oscillator frequency setting resistance
•Small start-up current............................................100µA 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
•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
•SOFT start function by expanding period
Output current...............................................................±1A
Output rise time 60ns,fall time 40ns
Modified totempole output method with small through current
makes the smoothing capacitor of the power input section small.
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.
14-pin DIP,16-pin SOP 1.5W(at 25°C)
Simplified peripheral circuit with protection circuit and built-in
large-capacity totempole output
method(CLM+pin)
•T-ON pin resistance R
•T-OFF pin resistance R
ON
OFF
...........................10k to 75k
..........................2k to 30k
(
1
/ 22 )
PIN CONFIGURATION (TOP VIEW)
HEAT SINK PIN
COLLECTOR
COLLECTOR
EMITTER
EMITTER
SWITCHING REGULATOR CONTROL
MITSUBISHI (Dig./Ana. INTERFACE)
REG
REG
V
OVP
V
DET
OVP
DET
F/B
F/B
OUT
OUT
Outline 16P2N-A
1
2
3
4
5
6
7
1
2
3
4
5
6
7
8
Outline 14P4
Connect the heat sink pin to GND.
M51996AP/FP
14
13
12
11
10
16
15
14
13
12
11
10
9
8
9
Vcc
CLM+
GND
Vcc
CLM+
T-OFF
T-ON
SOFT
HEAT SINK PIN
T-OFF
T-ON
SOFT
GND
CF
CF

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M51996FP Summary of contents

Page 1

... Supply voltage range............................................12 to 30V 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 REGULATOR UNDER VOLTAGE LOCK OUT LATCH OVP CF OSCILLATOR T-ON (TRIANGLE) T-OFF ABSOLUTE MAXIMUM RATINGS Symbol Parameter V Supply voltage CC V Collector voltage C I Output current O V terminal output current I REG VREG V SOFT ...

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) Vcc Vcc ,Vcc (START) (STOP) Stand-by current Icc L Operating circuit current Icc O Circuit current in OVP ...

Page 4

TYPICAL CHARACTERISTICS THERMAL DERATING (MAXIMUM RATING) 1800 1500 1200 900 600 300 100 AMBIENT TEMPERATURE Ta(°C) SOFT TERMINAL INPUT VOLTAGE VS. EXPANSION RATE OF PERIOD 5.0 (f 4.5 4 =15k ...

Page 5

CLM+ TERMINAL CURRENT VS. CLM+ TERMINAL VOLTAGE -400 -300 Ta=-30°C Ta=25°C Ta=85°C -200 -100 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 CLM+ TERMINAL VOLTAGE V OUTPUT HIGH VOLTAGE VS. SOURCE CURRENT 4.5 4.2 3.9 Vcc=18V ...

Page 6

VOLTAGE GAIN OF DETECTION AMP VS. FREQUENCY FREQUENCY f(Hz) ON duty VS. F/B ...

Page 7

ON duty VS. R OFF 100 OFF OSCILLATOR FREQUENCY VS. AMBIENT TEMPERATURE 700 R R 600 C 500 400 ...

Page 8

OVP TERMINAL INPUT VOLTAGE VS. INPUT CURRENT 1m Ta=85°C Ta=25°C Ta=-30°C 100µ 10µ 1µ 0.2 0.4 0.6 0.8 OVP TERMINAL INPUT VOLTAGE V 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 ...

Page 9

FUNCTION DESCRIPTION Type M51996AP and M51996AFP are especially designed for off-line primary PWM control IC of switching mode power supply to get DC voltage from AC power supply. Using this IC,smart SMPS can be realized with reasonable cost and compact ...

Page 10

Start-up circuit section The start-up current is such low current level as typical 100µ A,as shown in Fig.3,when the Vcc voltage is increased from low level to start-up voltage Vcc (START) In this voltage range,only a few parts in this ...

Page 11

SOFT(soft start) circuit is operating. Output transistor is protected from rush current by CLM function at the start time of power on.SOFT terminal is used to improve the rising response of the output voltage of power ...

Page 12

... The circuit diagram is quite similar to that of shunt regulator CLM type 431 as shown in Fig.13.As well known from Fig.13 and Fig.14,the output of OP AMP has the current-sink ability,when the DET terminal voltage is higher than 2. MITSUBISHI (Dig./Ana. INTERFACE) M51996AP/FP SWITCHING REGULATOR CONTROL ~ V 200mV THCLM TERMINAL OUT Fig ...

Page 13

F/B 10.8k 10S 1.2k Fig.13 Voltage detector circuit section(DET) but it becomes high impedance state when lower than 2.5V DET terminal and F/B terminal have inverting phase characteristics each other, recommended to connect the ...

Page 14

OVP RESET POINT 8.87V(-30°C) 7 8.94V(25°C) 9.23V(85° Ta=-30°C Ta=25°C 4 Ta=85° SUPPLY VOLTAGE Vcc(V) Fig.16 CIRCUIT CURRENT VS. SUPPLY VOLTAGE (OVP OPERATION) Output section It is required that the output ...

Page 15

M51996AP/FP. The input voltage(V ),at which the IC operation stops,is IN(STOP) decided by the ratio of third winding of transformer. The V and V are given by following equations. IN(START) IN(STOP • ...

Page 16

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 noise. The OVP terminal is connected with the sink current source ...

Page 17

Current limiting circuit (1)Peripheral circuit of CLM+ terminal Fig.25 shows the example circuit diagrams around the CLM+ terminal.It is required to connect the low pass filter,in order to reduce the spike current component,as the main current or drain current contains ...

Page 18

M51996A Fig.28 Relationship between REG terminal and F/B terminal If the curve becomes vertical because of an excess current, the output voltage is lowered and no feedback current flows from feedback photo-coupler;the PWM comparator operates to enlarge ...

Page 19

The DC output voltage of SMPS depends on the Vcc voltage of type M51996A when the polarity of the third winding is negative and the system is fly back.So the operation of type M51996A ...

Page 20

As the gate drive current may reach up to several tenths milliamperes at 500kHz operation,depending on the size of MOS-FIT,the power dissipation caused by the gate current can not be neglected. In this case,following action will be considered to avoid ...

Page 21

F/B M51996A TO PHOTO COUPLER How to get the narrow pulse width Fig.39 during the start of operation How to synchronize with external circuit Type M51996A has no function to synchronize with external circuit,however,there is some application circuit for synchronization ...

Page 22

Attention for heat generation The maximum ambient temperature of type M51996A is +85°C,however,the ambient temperature in vicinity of the IC is not uniform and varies place by place,as the amount of power dissipation is fearfully large and the power dissipation ...

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