Pulse transformers are used in high-frequency power converters whenever an electrical impulse has to be transferred from the control stage to the power stage, while maintaining galvanic isulation between the two circuits, in compliance with required safety standards.
The signal applied to the transformer’s primary winding is transferred to the secondary winding to enable the switching of an active electronic switch.
There are several control techniques used in high-frequency power conversion systems, which vary depending on the system power, the voltages and currents involved, and the type of application.
Once the drive technology has been selected, the designer can identify the pulse transformer best suited to the application.
Sirio pulse transformers are classified, by size and construction style, into series, each one with its own peculiarities.
We offer several standard pulse and gate drive transformers, listed below, suitable to a wide range of applications. Often, given the infinite possibilities for circuit solutions, it may be necessary to develop a special pulse transformer (custom design). Consulting the technical data of the standard codes gives a good overview of the performance offered by each pulse transformer series.
MINIMAL FOOTPRINT – Drive transformers Series 105
Extremely compact drive transformers with an extremely small footprint, wound on a toroidal ferrite core, usually with insulated wire, to ensure an insulation voltage of up to 4 kVrms. They feature a small transfer area (typically in the range of a few μVs) and low primary inductance. They are mainly used for high-frequency driving of MOSFETs.
| Code | n | Vt [μVs] | Ip [mArms] | Ls [nH] | Ck [pF] | Uis [Vrms] | Up [Vrms] | Drawing |
|---|---|---|---|---|---|---|---|---|
| TI 105630 | 1 : 1 | 5 | 400 | 180 | 9 | 700 | 4000 | 105A |
| TI 105645 | 1 : 1,25 : 1,25 | 5 | 400 | 150 | 10 | 700 | 4000 | 105B |
ULTRA-FLAT DESIGN – Drive transformers Series 106
Very compact and ultra-compact drive transformers, built on an E-shaped ferrite E core. They feature a transfer area up to a few hundred μVs and intermediate-values leakage inductance and coupling capacitance. They are primarily used for high-frequency driving of IGBTs and MOSFETs. Standard transformers are not available for this product family.
MINIMAL COUPLING CAPACITANCE – Pulse transformers Series 108
Pulse transformers built on an E core, with side-by-side windings. They feature a transfer area of a few hundred μVs. The key characteristics of these transformers is the low coupling capacitance, which is an extremely good condition to avoid spurious firing of switching devices. These components are primarily used for multiple-shot firing technique. The automatic manufacturing process enhances this type of product, offering an excellent quality/price ratio.
| Code | n | Vt [μVs] | Imax [mA] | tr [μs] | Rc [Ω] | Ck [pF] | Uis [Vrms] | Up [Vrms] | Drawing |
|---|---|---|---|---|---|---|---|---|---|
| TI 108001 | 1 : 1 | 500 | 100 | 3,0 | 100 | 10 | 500 | 4000 | 108A |
| TI 108010 | 1 : 1 | 250 | 250 | 1,5 | 40 | 7 | 500 | 3100 | 108A |
| TI 108030 | 2 : 1 | 350 | 250 | 3,5 | 40 | 8 | 500 | 3100 | 108A |
| TI 108050 | 3 : 1 | 300 | 250 | 2,5 | 40 | 8 | 500 | 3100 | 108A |
HIGHEST VERSATILITY – Pulse and drive transformers Series 109-117-118
Pulse transformers of various sizes built on E-shaped ferrite cores. These components offer great flexibility in varying key parameters, such as transfer area, turns ratio, nominal currents, and insulation level, can be varied. They are primarily used for high-frequency driving of IGBTs and MOSFETs. Standard versions feature one or two secondary windings. These transformers are designed for automatic production lines, ensuring consistent quality and construction while reducing production costs.
| Code | n | Vt [μVs] | Ip [mArms] | Lp [mH] | Ls [μH] | Ck [pF] | Uis [Vrms] | Up [Vrms] | Drawing |
|---|---|---|---|---|---|---|---|---|---|
| TI 109204 | 1 : 1 : 1 | 120 | 300 | 0,85 | 2,0 | 14 | 700 | 4200 | 109B |
| TI 109210 | 1 : 1 : 1 | 250 | 300 | 2,50 | 5,0 | 25 | 330 | 3100 | 109A |
| TI 109212 | 1 : 1 : 1 | 250 | 250 | 2,50 | 5,0 | 25 | 750 | 2000 | 109B |
| TI 109213 | 1,13 : 1 : 1 | 180 | 250 | 1,85 | 4,0 | 20 | 500 | 4000 | 109B |
| TI 109214 | 1,4 : 1 : 1 | 200 | 250 | 2,15 | 4,0 | 20 | 500 | 4000 | 109B |
| TI 109215 | 1 : 1,2 : 1,2 | 150 | 250 | 1,30 | 3,0 | 20 | 500 | 4000 | 109B |
| TI 109217 | 1 : 1 | 200 | 350 | 1,75 | 5,0 | 25 | 440 | 3750 | 109C |
| TI 117110 | 1 : 1 | 300 | 200 | 3,50 | 5,0 | 35 | 500 | 4000 | 117C |
| TI 117120 | 1 : 1 : 1 | 300 | 200 | 3,50 | 2,2 | 35 | 500 | 4000 | 117D |
| TI 117147 | 2 : 1 | 250 | 400 | 5,80 | 10,0 | 25 | 500 | 4000 | 117C |
| TI 117160 | 3 : 1 | 150 | 500 | 5,80 | 13,0 | 30 | 500 | 4000 | 117C |
| TI 117610 | 1 : 1 | 150 | 600 | 0,35 | 0,9 | 25 | 700 | 4000 | 117C |
| TI 117615 | 1 : 1 : 1 | 150 | 600 | 0,35 | 0,6 | 40 | 700 | 4000 | 117D |
| TI 118310 | 1 : 1 | 500 | 1000 | 1,0 | 10 | 50 | 500 | 4000 | 118E |
| TI 118320 | 1 : 1 : 1 | 500 | 1000 | 1,0 | 10 | 50 | 500 | 4000 | 118F |
| TI 118330 | 2 : 1 : 1 | 500 | 1000 | 1,0 | 10 | 50 | 500 | 4000 | 118F |
| TI 118350 | 1 : 1 : 1 | 1000 | 1000 | 2,0 | 20 | 55 | 500 | 4000 | 118F |
| TI 118370 | 3 : 1 : 1 | 300 | 1000 | 1,0 | 10 | 40 | 500 | 4000 | 118F |
HIGHEST COUPLING – Pulse transformers Series 111-112-113-114
These pulse transformers are built on toroidal cores of various sizes. They offer a wide range of characteristics, depending on the core’s magnetic material and winding construction. Ferrite cores are the most economical choice for high-frequency applications. Alternatively, cores made of metal alloy laminations are available, which feature a higher nominal magnetic induction, allowing for more compact designs, and extremely stable temperature behavior, making them suitable for extreme environmental conditions. Among the various options, the most commonly used construction is multi-strand winding, which provides the transformer extremely fast response times. Standard versions include one or two secondary windings.
| Code | n | Vt [μVs] | Imax [mA] | tr [μs] | Rc [Ω] | Ck [pF] | Uis [Vrms] | Up [Vrms] | Drawing |
|---|---|---|---|---|---|---|---|---|---|
| TI 111010 | 1 : 1 | 200 | 400 | 1 | 27 | 160 | 380 | 2000 | 111A |
| TI 111020 | 1 : 1 : 1 | 200 | 400 | 1 | 27 | 160 | 380 | 2000 | 111B |
| TI 112130 | 1 : 1 | 500 | 2000 | 1 | 15 | 70 | 500 | 4000 | 112A |
| TI 112140 | 1 : 1 : 1 | 500 | 2000 | 1 | 15 | 70 | 500 | 4000 | 112B |
| TI 113150 | 1 : 1 | 1000 | 2000 | 1 | 10 | 100 | 500 | 5000 | 113A |
| TI 113160 | 1 : 1 : 1 | 1000 | 2000 | 1 | 10 | 100 | 500 | 5000 | 113B |
| TI 114070 | 1 : 1 | 2000 | 2000 | 1 | 8 | 230 | 380 | 3100 | 114A |
| TI 114080 | 1 : 1 : 1 | 2000 | 2000 | 1 | 8 | 230 | 380 | 3100 | 114B |
HIGHEST CUSTOMIZATION – Pulse and drive transformers Series 116
When none of the standard sizes meet the required electrical characteristics, the pulse transformer will fall within the generic 116 series. Typically, two transformers belonging to this family share no common features, except that they are developed exclusively to the customer’s specifications.
Sirio generally uses standard raw materials, thus benefiting from economies of scale and reducing delivery times, even for special components.
- n ratio between the turns of the primary winding and the secondary winding
- Vt minimum voltage*time area of the unipolar pulse (called transfer area) that can be transferred to the secondary without causing saturation of the magnetic material, referred to a temperature of 25°C
- LP primary winding inductance
- Ck coupling capacitance between the windings
- Ls primary leakage inductance, equal to the inductance value measured across the primary winding with the secondary winding short-circuited
- tr rise time, equal to the time the transformer takes to transfer the pulse to the secondary, if the nominal load resistance Rc is connected
- Imax maximum secondary current available with a rise time equal to or less than tr (on the nominal load resistance Rc)
- Ip rms nominal primary current (thermal current)
- Uis maximum working voltage between two windings
- Up insulation voltage between two windings windings