Cores amorphous with a rectangular hysteresis loop

MSSA series

Toroidal saturation cores with a rectangular hysteresis loop, made from a thin (18–20 μm) amorphous ribbon AMAG 172 based on cobalt, are traditionally considered the best for use in magnetic amplifier chokes (AM). MU technology is synonymous with reliability in modern switching power supplies.

In most multichannel power supplies, only one output voltage is regulated by a common feedback loop from the output of this channel to the PWM regulator. The dynamic properties of the remaining channels are much worse, they are dependent on each other. For independent stabilization of the channel voltage, various adjustment methods are additionally used. Conventional linear regulators reduce efficiency and are only acceptable for low output currents. Electronic governors are more efficient, but also more bulky due to the larger number of components and are therefore less reliable and more expensive.

The use of a magnetic amplifier is a cheap, effective and reliable solution to these problems. It easily achieves efficiency levels of more than 90% at switching frequencies up to 300 kHz, contributing to the miniaturization of equipment.

 

Dimensions and main characteristics

MSSA series

  • L - type of heat treatment: in the longitudinal field;
  • N - type of heat treatment: no field
Core name ​​

Dimensions 1)

in container
(without container)
(D-d-H)
(mm)

 Leff 2)
(mm)		 Aeff 3)
(mm2)		 Veff 4)
(mm3)		 Wa 5)
(mm2)		 m 6)
(g)		 2Φm 7)
(μVb)
± 15%

 

In a plastic container
MSSA-09S-L

10.7 - 5.5 - 6.3
(9,0 - 7,0 - 4,5)
 25.1 3.6 88 24 0.70 4.1
MSSA-09S-N

MSSA-10S-L

11.9 - 5.8 - 6.3
(10,0 - 7,3 - 4,5)
 27.2 4.9 129 26 1.02 5.5
MSSA-10S-N

MSSA-10B-L

11.2 - 5.7 - 5.7
(10,0 - 6,7 - 4,5)
 26.2 5.94 157 26 1.20 6.9
MSSA-10B-N

MSSA-11A-L

14.0 - 6.6 - 4.8
(11,2 - 8,0 - 3,0)
 30.1 3.84 113 34 0.89 4.3
MSSA-11A-N

MSSA-11S-L

14.0 - 6.6 - 6.3
(11,2 - 8,0 - 4,5)
 30.1 5.76 196 34 1.34 6.6
MSSA-11S-N

MSSA-12A-L

14.0 - 6.6 - 4.8
(12,0 - 8,0 - 3,0)
 31.4 4.8 147 34 1.16 5.4
MSSA-12A-N

MSSA-12S-L

14.0 - 6.6 - 6.3
(12,0 - 8,0 - 4,5)
 31.4 7.2 221 34 1.74 8.1
MSSA-12S-N

MSSA-13B-L

14.7 - 7.8 - 4.6
(12,8 - 9,5 - 3,2)
 35.0 4.2 144 48 1.14 4.8
MSSA-13B-N

MSSA-14S-L

15.9 - 6.8 - 6.5
(14,0 - 8,3 - 4,5)
 35.0 10.3 350 36 2.76 11.6
MSSA-14S-N

MSSA-15A-L

16.7 - 10.5 - 6.3
(15,0 - 12,0 - 4,5)
 42.4 5.4 223 87 1.76 6.1
MSSA-15A-N

MSSA-15S-L

16.9 - 8.6 - 6.5
(15,0 - 10,0 - 4,5)
 39.3 9.0 355 58 2.72 10.5
MSSA-15S-N

MSSA-16B-L

17.8 - 11.0 - 5.1
(15,9 - 12,7 - 3,2)
 44.9 4.1 179 95 1.42 4.6
MSSA-16B-N

MSSA-16D-L

17.8 - 8.3 - 8.1
(15,4 - 10,0 - 6,0)
 39.9 13.0 504 54 3.98 14.8
MSSA-16D-N

MSSA-16A-L

17.8 - 8.3 - 8.1
(16,0 - 10,0 - 6,0)
 40.8 14.4 588 54 4.53 16.7
MSSA-16A-N

MSSA-18S-L

19.8 - 10.4 - 6.4
(18,0 - 12,0 - 4,5)
 47.1 10.8 496 85 3.92 12.2
MSSA-18S-N

MSSA-18D-L

20.0 - 8.7 - 12.0
(17,4 - 12,0 - 10,0)
 46.2 21.6 973 59 7.68 24.4
MSSA-18D-N

MSSA-19B-L

21.2 - 11.0 - 5.1
(19,2 - 12,7 - 3,2)
 50.1 8.3 407 95 3.21 9.4
MSSA-19B-N

MSSA-19A-L

21.6 - 11.0 - 7.9
(19,5 - 12,7 - 6,0)
 50.6 16.3 805 95 6.35 18.5
MSSA-19A-N

MSSA-20A-L

22.5 - 10.4 - 10.1
(20,0 - 12,5 - 8,0)
 51.0 24.0 1195 85 9.43 27.1
MSSA-20A-N

MSSA-21S-L

22.8 - 12.4 - 6.3
(21,0 - 14,0 - 4,5)
 55.0 12.6 675 121 5.33 14.3
MSSA-21S-N

MSSA-25A-L

27.7 - 17.3 - 12.9
(25,0 - 20,0 - 10,0)
 70.7 20.0 1378 235 10.9 22.6
MSSA-25A-N

MSSA-25S-L

28.4 - 13.8 - 12.2
(25,0 - 16,0 - 10,0)
 64.4 36.0 2261 150 17.8 40.7
MSSA-25S-N

Note:

  1. Nominal dimensions of the finished magnetic circuit in the container. Ext. dia. - Int. dia. - Height.
  2. Nominal values of the length of the middle magnetic line.
  3. The nominal values of the effective cross-sectional area.
  4. Nominal values of effective volume.
  5. The nominal values of the window area.
  6. Nominal values of the mass of the magnetic circuit without container.
  7. Full (double) flow at a frequency of 100 kHz, 80 A/m and + 25 °C.
  • * L - annealing in a longitudinal magnetic field, N - annealing without a magnetic field.
  • Squareness coefficient, Br/Bm in 100 kHz mode, 80 A/m and +25 °C for type L cores more than 97%, for type N - more than 96%. In 1 kHz mode, 80 A/m and +25 ° C for type L more than 93%, for type N more than 86%.
  • Coercive force, Hc below 17 A/m (typical value 12 A/m) at 100 kHz, 80 A/m and +25 °C.
  • By agreement, it is possible to provide the printed parameters of the sampling hysteresis loop in order to select matched pairs, etc.

 

​ Application Information (MSSA series)

​ Program for calculating inductors of magnetic amplifiers

Application

  • Magnetic Amplifiers for Switch Mode Power Supplies
  • Magnetic amplifiers for DC / DC converters
  • Computer power supplies
  • Pulse transformers
  • Saturating transformers for autogeneraors
  • Other saturation devices

 

Advantages

  • High squareness (reducing the dead time of the MU throttle and improving the adjustment mode)
  • High saturation induction (downsizing of chokes)
  • Very low coercive force (reduction of reverse recovery current and overheating of regulator components)
  • Low losses in the magnetic circuit (increase in operating frequencies)

 

Additional parameters and characteristics

Specific Magnetic Loss Pcm (f, ΔB) - MSSA-XXX-L Series
* Losses are measured in the mode of sinusoidal bipolar change of induction from –B to + B
Temperature dependence Bm (T)
* At high temperatures, the designer needs to account for the decrease in induction and total (double) flow with increasing temperature.
Dependence of the squareness coefficient on frequency
* The squareness coefficient of the MSSA-XXX-L series grows negligibly with the magnetizing frequency, which is optimal for highly stable multichannel SMPS.
Frequency dependence of permeability
* Permeability in the MSSA-XXX-L series is highly frequency dependent, which must be taken into account to design a stable feedback loop in a power supply circuit.
Frequency dependence of Hc
* Low coercive force allows operation at conversion frequencies up to 300 kHz.
Temperature dependence of Br / Bm
* The squareness coefficient of the MSSA-XXX-L series grows negligibly with the magnetizing frequency, which is optimal for highly stable multichannel SMPS.

The main characteristics of the material used

  • Material AMAG 172
  • Amplitude of induction, Вm (25°C) 0,60 T
  • Amplitude of induction, Вm (90°C) 0,54 T
  • Squareness coefficient Br/Bm (at 100 kHz, 80 A/m), not less than 0.96
  • Squareness coefficient Br/Bm (at 1 kHz, 80 A/m), not less than 0.93 (L-type)
  • Squareness coefficient Br/Bm (at 1 kHz, 80 A/m), not less than 0.86 (N-type)
  • Specific power losses Psp (at 50 kHz, 0.4 T), no more than 60 W/kg
  • Coercive force Nc (at 100 kHz, 80 A/m), no more than 17 A/m
  • Curie temperature, Tc 235°C
  • Operating temperature range from –60 °C to + 100 °C
  • Saturation magnetostriction less than 0,1×10-6

Design

The twisted tape magnetic core is placed in a rigid protective container made of glass-filled polyamide and mechanically fixed with silicone sealant. The container has rounded edges and is designed for direct wrapping with thick wire. The container provides reliable mechanical protection of the amorphous material and the preservation of its properties.

Recording example

MSSA-10S-L, where:

  • MS - MSTATOR;
  • S - application (saturation core);
  • A - material designation;
  • 10 - outer diameter, mm;
  • S - sectional designation;
  • L - type of heat treatment: in prod. field;
  • N - type of heat treatment: no field