Reactor RM6203 Schematics

RM6203

High Performance Current Mode PWM Switching Power Supply controller

DESCRIPTION

The RM6203 is a current mode PWM switching power

supply controller that specifically designed for AC/DC

converter with high performance versus cost ratio. It provides

continuous output power up to 12W in the broad voltage range

of 85V – 265V.Its optimized and highly reasonable circuit

design has made it possible to minimize the total cost of the

product. This power supply controller could be used in typical

flyback circuit topology to constitute simple AC/DC converter.

The internal initiating circuit of RM6203 has been designed

with a unique means of current sink to complete the startup

using the amplifying function of the power switching tube. This

will significantly reduce the power consumption of the start-up

resistor; and when the output power becomes smaller,

RM6203 will automatically lower its operating frequency to

enable very low standby power consumption.

When the power tube stops, the internal circuit will turn

the power tube reverse bias to greatly raise the voltage

resistant capacity of OC pin. This will ensure the safety of the

power tube. The internal design of the RM6203 is also

provided with over-load and saturation preventive function

capable of preventing disorders such as overload, transformer

saturation and output short-circuit, so as to increase the

reliability of the power supply. A voltage reference of 2.5V is

also integrated in the RM6203 to provide accurate power

supply to the clock circuit, and the clock frequency may be set

by external timing capacitance. Presently, standard DIP8

package and environmental friendly lead-free package in

compliance with European standard can be supplied.

FEATURES

■ Built-in 700V high voltage power switching tube with

minimal external parts count

■ Latched PWM and pulse-by-pulse current limiting

inspection

■ Reduced frequency at low output with standby power

consumption below 0.25W

■ Built-in slope and feedback compensation function

■ Separate upper limit current inspection controller to

handle timely the over-current and overload of the controller

■ Turn off periodic bias output of the emitter to improve the

voltage resistance of the power tube

■ Built-in thermal protective circuit

■ Complete start-up using amplification of the switching

power tube to reduce the power consumption of the start-up

resistor more than ten times

■ Automatic VCC over-voltage limit

■ Broad voltage output power up to 5W and narrow voltage

output power up to 8W

Applications

■ Power Adaptors(traveling chargers ,stand-alone power

set)

■ Internal power supply for Energy-Saving Appliances (such

as electromagnetic oven, microwave oven and etc.)

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RM6203

TYPICAL APPLICATION

PACKAGE INFORMATION

PIN FUNCTIONS

Pin Symbol Function Description

1 OB Base Pin of the Power Tube.(Enabling current input and connect to initiating

2 VCC Power Supply Pin
3 GND Ground Pin
4 CT Oscillation Capacitance Pin.(Connect to timing capacitance)
5 FB Feedback Pin
6 IS Current Inspection Pin

7、8

OC Output Pin( Connect to switching transformer)

TOP VIEW

DIP-8

resistance)

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RM6203

ABSOLUTE MAXIMUM RATINGS(Note 1)

Supply Voltage VCC…………………………….… 18V Pin Input Voltage………………………………… VCC+0.3V

OC Voltage……………………………..…… -0.3-700V Switching Current………………….………………… 800mA

Total Dissipation Power………………..…… 1000mW Operating Temperature Range……..……………… 0-75℃

Storage Temperature Range…………… -40 - 150℃ Welding Temperature……......……………… +260℃，10S

ELECTRICAL CHARACTERISTICS

The specifications are applied at T=25℃, VCC=5.5-7.5V, Ct=680PF, RS=1Ω, unless otherwise noted.(Note 2)

Parameter Symbol Conditions Min Typ Max Units

Output Section

Max. Withstanding Voltage of
the Switching Tube
Saturation Voltage V

Output Rise Time TR CL=1nF 75 ns
Output Fall Time TF CL=1nF 75 ns
Output Limiting Current

Reference Section

Reference Output Voltage V
Line Regulation Vcc=5.5-9V 2 20 mV
Load Regulation Io=0.1-1.2mA 3 %
Temperature Stability 0.2
Output Noise Voltage F=10Hz-10KHz 50 uV
Long Term Stability

Oscillator Section

Oscillating Frequency F
Voltage Stability Vcc=5.5-9V 1 %
Temperature Stability
Oscillator Amplitude (Vp - p) 2.2 V

Feedback Section

Pull-up

Impedance

Current
Pull-Down

Resistor
Power Supply Suppression
Ratio

Current Sampling Section

Current Sampling Threshold V
Anti-Upper Limit Current IL 0.25 0.27 0.29 A
Power Supply Suppression

Ratio

PWM Section

Maximum Duty Ratio D
Minimum Duty Ratio D

Power Supply Current Section

Initiating Reception Current 1.6 2.4 3.2 mA
Initiating Static Current 55 80 uA
Static Current I
Start-up voltage 7.6 7.8 8.0 V
Oscillator Turn-off Voltage 4.2 4.4 4.6 V

I

SAT

REF

=10mA 700 V

OC

Ioc=250mA 1 V

Tj=0-100℃

250 270 290 mA

Io=1.0mA 2.4 2.5 2.6 V

mV/℃

1000 hours@85℃

Ct=680PF 59 66 73 KHz

OSC

Ta=0-85℃

FB=2.5V, IS=0V 0.55 0.6 0.65 mA Input

5 mV

1 %

30 KΩ

Vcc=5.5-9V 60 70 dB

CS

0.55 0.60 0.65 V

60 70 dB

MAX

MIN

Q

53 57 61 %

3.5 %

Vcc=8V 2.8 mA

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