Home / Reference Designs / TIDA-010081
Magnetics for the TIDA-010081 1 kW PFC and LLC power supply
TIDA-010081 is a Texas Instruments reference design for a 1 kW, 54 V telecom power supply with a CCM boost PFC and a half-bridge LLC. Its design guide gives the electrical values of the PFC inductor, the LLC transformer and the resonant inductor, and the bill of materials shows that all three are custom parts made for the board, with no public datasheet. When an engineer asked TI's support forum for this transformer, the answer was to have it made by a magnetics supplier. We build these parts from the published values or from your modified ones.
What the board is
- 85 to 265 V AC input, 54 V output at 18.7 A, 1009.8 W.
- CCM boost PFC with the UCC28180 at 65 kHz, followed by a half-bridge LLC with the UCC256403 and synchronous rectification with the UCC24624.
- Auxiliary flyback with the UCC28911 and three isolated outputs, from 100 to 450 V DC.
- 95.9 % peak efficiency at 230 V AC, and at least 95 % from 30 to 100 % load.
Source: Texas Instruments TIDA-010081 product page, design guide TIDUET4A, schematic TIDM325 and bill of materials TIDM326, checked November 2026.
The magnetics on the board
| Part | What the design files publish | What decides the design |
|---|---|---|
| PFC boost inductor, L1 | Design guide: 566 µH minimum, 2.67 A of ripple (30 % of the 8.9 A peak input current), 65 kHz, duty cycle up to 0.674. The inductor therefore carries a peak of 10.24 A. BOM: custom PFC inductor of 532 µH | Inductance held at the 10.24 A peak current and at low line, core loss with 65 kHz ripple on a 50 Hz current |
| LLC transformer, T1 | n = 3.6, Lm = 144 µH, centre-tapped secondary, primary 7.66 A, each secondary half 16 A, 450 V AC primary, 54 V AC secondary, 44.2 to 118 kHz, reinforced insulation to IEC 60950. BOM: custom transformer of 144 µH | Lm tolerance, AC resistance of the centre-tapped secondary at 16 A, reinforced insulation with low leakage |
| LLC resonant inductor, Lr, L4 | 16 µH, discrete, 7.66 A rated, 34 V across it at 44.2 kHz. BOM: custom resonant inductor of 16 µH | Value and tolerance at 100 kHz, losses with a 442 V peak on the resonant capacitor |
| Resonant capacitor, Cr | 0.164 µF, as two 0.082 µF, 630 V DC film capacitors in the BOM | Not a magnetic, but it fixes the tank with Lr |
| Auxiliary transformers, T2 and T3 | T2: custom flyback transformer of 1.6 mH on an EE16 core for the UCC28911, three isolated outputs from 100 to 450 V DC. T3: 100 µH transformer on an EP10 core for a second auxiliary rail | Turns, gap and isolation for the bias rails |
| EMI filter, L2 and L3 | A 2 × 2 mH, 10 A coupled inductor and a 4 mH common mode choke rated for 1 kW | Attenuation measured on the real supply |
| Output filter inductor, L5 | 300 nH, 32 A, the small second-stage filter the guide mentions | Inductance at 18.7 A plus ripple, DC resistance |
Checks we ran on the published values
- Lr = 16 µH and Cr = 0.164 µF give a series resonance of 98.3 kHz. TI sets the nominal frequency at 100 kHz.
- Lm + Lr = 160 µH with the same Cr gives the lower resonance at 31.1 kHz, below the 44.2 kHz minimum switching frequency.
- Lm / Lr = 9. The design guide text says Ln = 8. The published values give 9.
- With n = 3.6 and unity gain, the half-bridge needs about 389 V on the DC link, which matches a 390 V PFC output.
- The magnetising current at 100 kHz is about 6.8 A peak to peak, which is what provides ZVS at light load.
- The PFC inductor in the BOM, 532 µH, is about 6 % below the 566 µH minimum the guide calculates for 30 % ripple. With 532 µH the ripple at low line rises to about 2.84 A, which is 32 % of the 8.9 A peak input current.
Why it is not a catalogue part
The transformer combines a defined magnetising inductance, a centre-tapped secondary carrying 16 A per half for synchronous rectification and reinforced insulation, in the space of a 1 kW board. Catalogue LLC transformers rarely match n, Lm and the insulation at the same time, and a 10 % change in Lm moves both the light load ZVS margin and the gain at low frequency.
If you change the design
A 48 V or 12 V output changes n and the secondary current. A different PFC output voltage changes n too. A higher power or a smaller case changes the core size of all three magnetics and the losses each one is allowed. We recompute the tank with you before designing the parts.
What to send us
The reference number, your Lm, Lr, n and frequency range if you changed them, output voltage and power, the insulation standard, the case dimensions and maximum ambient, and the quantities you expect.
We aim to send an engineering answer with a first design proposal inside 24 hours, then 4 to 8 weeks from an agreed design to a prototype, subject to raw material stock. No minimum order quantity.
Straight answers