CL-130 - GE - Product.Network

Sensing

NTC Inrush Current Limiter is a

Thermometrics product.

Thermometrics has joined other

GE high-technology sensing

businesses under a new name—

GE Industrial, Sensing.

Features

• Low cost, solid state device for inrush current

suppression

• Excellent mechanical strength

• Wide operating temperature range: -58°F to 347°F

(-50°C to 175°C)

• Suitable for PCB mounting

• Available as a standard with kinked or straight leads

and on tape and reel to EIS RS-468A for automatic

insertion

Applications

Control of the inrush current in switching power supplies,

flourescent lamp, inverters, motors, etc.

• Low steady resistance and accompanying power loss

• Small size

• Low cost solid state sensor

Thermometrics

Thermistors

NTC Inrush

Current Limiter

Sensing

Options

• For kinked leads, add suffix “A”

• For tape and reel, add suffix “B”

• Other tolerances in the range 0.7 Ωto 120 Ω

• Other tolerances, tolerances at other temperatures

• Alternative lead lengths, lead materials, insulations

Data

*maximum rating at 77°F (25ºC) or

Iderated = √(1.1425–0.0057 x TA) x Imax @ 77°F (25°C) for

ambient temperatures other than 77°F (25ºC).

**maximum ratings

***R0=X1Ywhere X and Y are found in the table below

Type Res Max* Disc Disc Lead Lead Cx(max)** Equation constants for Approx. Res. Under Load at %

Fig. 1 @ 77°F Steady Dia. Thick. Spacing Dia.

µµFarads resistance under load *** Maximum Rated Current

(25°C) State (Max) (Max) (Ref.) AWG

±25% Current in in in @120 @240 X Y Current 25% 50% 75% 100% Diss. Time

(ΩΩ) AMPS (mm) (mm) (mm) VAC VAC Range Const. Const.

(RMS) Min. I / Max. I (mW/°C) (sec.)

CL-11 0.7 12 0.77 0.22 0.328 18 2700 600 0.50 -1.18 4.0≤1≤12 14 0.06 0.04 0.02 25 100

(19.55) (5.58) (8.33)

CL-21 1.3 8 0.55 0.21 0.328 18 800 200 0.60 -1.25 3.0≤1≤8.0 0.25 0.09 0.06 0.04 15 60

(13.97) (5.334) (8.33)

CL-30 2.5 8 0.77 0.22 0.328 18 6000 1500 0.81 -1.25 2.5≤1≤ 8.0 0.34 0.14 0.09 0.06 25 100

(19.55) (5.58) (8.33)

CL-40 5 6 0.77 0.22 0.328 18 5200 1300 1.09 -1.27 1.5≤1≤6.0 0.65 0.27 0.16 0.11 25 100

(19.55) (5.58) (8.33)

CL-50 7 5 0.77 0.26 0.328 18 5000 1250 1.28 -1.27 1.5≤1≤5.0 0.96 0.40 0.24 0.16 25 120

(19.55) (6.60) (8.33)

CL-60 10 5 0.77 0.22 0.328 18 5000 1250 1.45 -1.30 1.2≤1≤5.0 1.09 0.44 0.26 0.18 25 100

(19.55) (5.58) (8.33)

CL-70 16 4 0.77 0.22 0.328 18 5000 1250 1.55 -1.26 1.0≤1≤4.0 1.55 0.65 0.39 0.27 25 100

(19.55) (5.58) (8.33)

CL-80 47 3 0.77 0.22 0.328 18 5000 1250 2.03 -1.29 0.5≤1≤3.0 2.94 1.20 0.71 0.49 25 100

(19.55) (5.58) (8.33)

CL-90 120 2 0.93 0.22 0.328 18 5000 1250 3.04 -1.36 0.5≤1≤2.0 7.80 3.04 1.75 1.18 30 120

(23.62) (5.58) (8.33)

CL-101 0.5 16 0.93 0.22 0.328 18 4000 1000 0.44 -1.12 4.0≤1≤16 0.09 0.04 0.03 0.02 30 120

(23.62) (5.58) (8.33)

CL-110 10 3.2 0.40 0.17 0.250 24 600 150 0.83 -1.29 0.7≤1≤3.2 1.10 0.45 0.27 0.18 8 30

(10.16) (4.31) (6.35)

CL-120 10 1.7 0.40 0.17 0.250 24 600 150 0.61 -1.09 0.4≤1≤1.7 1.55 0.73 0.46 0.34 4 90

(10.16) (4.31) (6.35)

CL-130 50 1.6 0.45 0.17 0.250 24 600 150 1.45 -1.38 0.4≤1≤1.6 5.13 1.97 1.13 0.75 8 30

(11.45) (4.31) (6.35)

CL-140 50 1.1 0.45 0.17 0.250 24 600 150 1.01 -1.28 0.2≤1≤1.1 5.27 2.17 1.28 0.89 4 90

(11.45) (4.31) (6.35)

CL-150 5 4.7 0.55 0.18 0.328 22 1600 400 0.81 -1.26 1.0≤1≤4.7 0.66 0.27 0.16 0.11 15 110

(13.97) (4.57) (8.33)

CL-160 5 2.8 0.55 0.18 0.328 22 1600 400 0.60 -1.05 0.8≤1≤2.8 0.87 0.42 0.27 0.20 9 130

(13.97) (4.57) (8.33)

CL-170 16 2.7 0.55 0.18 0.328 22 1600 400 1.18 -1.28 0.5≤1≤2.7 1.95 0.80 0.48 0.33 15 110

(13.97) (4.57) (8.33)

CL-180 16 1.7 0.55 0.18 0.328 22 1600 400 0.92 -1.18 0.4≤1≤1.7 2.52 1.11 0.69 0.49 9 130

(13.97) (4.57) (8.33)

CL-190 25 2.4 0.55 0.18 0.328 22 800 200 1.33 -1.34 0.5≤1≤2.4 2.63 1.04 0.60 0.41 15 110

(13.97) (4.57) (8.33)

CL-200 25 1.7 0.55 0.18 0.328 22 800 200 0.95 -1.24 0.4≤1≤1.7 2.74 1.18 0.70 0.49 9 130

(13.97) (4.57) (8.33)

CL-210 30 1.5 0.40 0.20 0.250 24 600 150 1.02 -1.35 0.3≤1≤1.5 3.83 1.50 0.87 0.60 8 30

(10.16) (5.08) (6.35)

Type CL

Specifications

NTC discs for inrush current limiting

Description

Disc thermistor with uninsulated lead-wires.

Sensing

Inrush CurrentLimiters In Switching Power Supplies

The problem of current surges in switch-mode power

supplies is caused by the large filter capacitors used to

smooth the ripple in the rectified 60 Hz current prior to

being chopped at a high frequency. The diagram above

illustrates a circuit commonly used in switching power

supplies.

In the circuit above the maximum current at turn-on is

the peak line voltage divided by the value of R; for 120 V,

it is approximately 120 x √2/RI. Ideally, during turn-on RI

should be very large, and after the supply is operating,

should be reduced to zero. The NTC thermistor is ideally

suited for this application. It limits surge current by

functioning as a power resistor which drops from a high

cold resistance to a low hot resistance when heated by

the current flowing through it. Some of the factors to

consider when designing NTC thermistor as an inrush

current limiter are:

• Maximum permissible surge current at turn-on

• Matching the thermistor to the size of the filter capacitors

• Maximum value of steady state current

• Maximum ambient temperature

• Expected life of the power supply

Maximum Surge Current

The main purpose of limiting inrush current is to prevent

components in series with the input to the DC/DC

convertor from being damaged. Typically, inrush

protection prevents nuisance blowing of fuses or

breakers as well as welding of switch contacts. Since

most thermistor materials are very nearly ohmic at any

given temperature, the minimum no-load resistance of

the thermistor is calculated by dividing the peak input

voltage by the maximum permissible surge current in the

power supply (Vpeak/Imax surge).

Energy Surge at Turn-On

At the moment the circuit is energized, the filter caps in a

switcher appear like a short circuit which, in a relatively

short period of time, will store an amount of energy equal

to 1/2CV2. All of the charge that the filter capacitors store

must flow through the thermistor. The net effect of this

large current surge is to increase the temperature of the

thermistor very rapidly during the period the capacitors

are charging. The amount of energy generated in the

thermistor during this capacitor-charging period is

dependent on the voltage waveform of the source

charging the capacitors. However, a good approximation

for the energy generated by the thermistor during this

period is 1/2CV2(energy stored in the filter capacitor). The

ability of the NTC thermistor to handle this energy surge

is largely a function of the mass of the device. This logic

can be seen in the energy balance equation for a

thermistor being self-heated:

Input Energy = Energy Stored + Energy Dissipated

or in differential form:

Pdt = HdT + δ(T – TA)dt

where:

P = Power generated in the NTC

t = Time

H = Heat capacity of the thermistor

T = Temperature of the thermistor body

δ= Dissipation constant

TA= Ambient temperature

During the short time that the capacitors are charging

(usually less than 0.1 second), very little energy is

dissipated. Most of the input energy is stored as heat in

the thermistor body. In the table of standard inrush

limiters there is listed a recommended value of maximum

capacitance at 120 V and 240 V. This rating is not

intended to define the absolute capabilities of the

thermistors; instead, it is an experimentally determined

value beyond which there may be some reduction in the

life of the inrush current limiter.

Maximum Steady-State Current

The maximum steady-state current rating of a thermistor

is mainly determined by the acceptable life of the final

products for which the thermistor becomes a

component. In the steady-state condition, the energy

balance in the differential equation already given reduces

to the following heat balance formula:

Power = I2R = δ(T – TA)

As more current flows through the device, its

steady-state operating temperature will increase and its

resistance will decrease. The maximum current rating

correlates to a maximum allowable temperature.

In the table of standard inrush current limiters is a list of

values for resistance under load for each unit, as well as

a recommended maximum steady-state current. These

ratings are based upon standard PC board heat sinking,

with no air flow, at an ambient temperature of 77° (25°C).

However, most power supplies have some air flow, which

further enhances the safety margin that is already built

into the maximum current rating. To derate the

maximum steady state current for operation at elevated

ambient temperatures, use the following equation:

Iderated = Iderated = √(1.1425–0.0057 x TA) x Imax @ 77°F

(25°C)

Typical power

supply circuit

-to

DC/DC

converter

920-325A

All specifications are subject to change for product improvement without notice.

GE®is a registered trademark of General Electric Co. Other company or product

names mentioned in this document may be trademarks or registered trademarks

of their respective companies, which are not affiliated with GE.

www.gesensing.com

Sensing

For the Reduction of Inrush Current

A power thermistor is a type of NTC thermistor used for

the reduction of large inrush currents. These large inrush

currents are typically caused by charging of filter

capacitors in switching power supplies.

Power Thermistor

Specification

Parts D T(max.) L d F H1(±2.5) W1(min.)

7 7.0±1.5 5.2 18.5 0.6 5.0 15.5 1.5

9 9.0±1.5 6.0 18.5 0.6 5.0 17.0 1.5

11 11.0±1.5 6.5 18.5 0.8 7.5 19.5 2.0

13 13.5±1.5 8.0 18.5 0.8 7.5 21.5 2.0

15 15.0±1.5 9.0 18.5 0.8 7.5 23.5 2.0

18 18.0±1.5 9.0 18.5 1.0 10.0 27.0 3.0

Parts Type Normal Normal Dissipation Max. Time

no load ββconstant factor Permissible Constant

Diam resistance (K) (mW/°C) Current at (sec)

(mm) (ΩΩ) 77°F (25°C)

TP7D7 7 3000 9.8 2.4 70

TP8D7 8 3000 10.0 2.3 70

7ΦTP10D7 10 3000 10.3 2.0 80

TP16D7 16 3000 10.5 1.6 100

TP22D7 22 3100 9.5 1.4 120

TP5D9 5 3000 11.0 3.0 110

TP8D9 8 3000 14.2 2.7 120

9ΦTP10D9 10 3000 12.9 2.3 130

TP16D9 16 3100 10.2 1.7 160

TP4R7D11 4.7 3000 15.0 3.7 90

TP5D11 5 3000 15.0 3.3 130

11ΦTP8D11 8 3000 17.6 2.6 160

TP10D11 10 3100 17.4 2.4 170

TP4R7D13 4.7 3000 15.0 4.3 110

TP5D13 5 3000 15.0 3.4 125

13ΦTP8D13 8 3100 17.0 2.7 160

TP10D13 10 3100 13.8 2.5 180

TP3D15 3 3000 16.5 4.0 165

TP5D15 5 3100 17.7 3.7 170

15ΦTP8D15 8 3100 21.7 3.1 180

TP10D15 10 3100 19.9 2.9 200

TP4D18 4 3000 22.2 4.1 170

18ΦTP5D18 5 3000 24.0 3.8 180

TP8D18 8 3100 26.8 3.1 220

TP10D18 10 3100 27.8 2.8 260

* The resistance tolerance is ± 10% for standard devices.

* The b constant is determined by the equation :

= 1779.7 ln (R25/R85) ...R25 and R85 represent

the thermistor resistance at 77°F and 185°F (25ºC and 85ºC) respectively.

* For non-standard devices consult Thermometrics global business.

Power thermistor standard dimensions

Power thermistor application circuits

Code Designation

T P 8 D 13 L K B E S M N R

1 23456789 1011

1 Shape: Power thermistor

2 Resistance at 77°F (25°C): 8 = 8 S, 4R7 = 4.7 S

3 Diameter size: D7, D9, ...D18

4/5 Resistance and B constant tolerance: K: ±10%, L: ±15%

6 Lead wire center-to-center: (F): A: 0.19 in (5 mm), B: 0.29 in (7.5 mm),

C: 0.39 in (10 mm)

7 Lead wire style: D: Straight, E: Inside kink, F: Outside kink

8 Lead wire length: G: 0.19 in (5 mm), H: 0.27 in (7 mm), I: 0.35 in (9 mm),

...S: Other dimensions

9 Y-Form: J: Yes, M: No

10 MK part number marking: N: No, O: Yes

11 Packing form: Taping P: 15 pitch, Q: 30 pitch, Others: R: Bulk, S: Paper pad,

T: Element

Inside Kink: E

Outside Kink: F

Straight: D

No: M

Yes: J

Lead Wire Style

Y-Form

Units:

in (mm)

H1 L

Resin coated Pb/Sn-plated

copper wire

P: Th P: Th

P: Th