Datasheet InnoSwitch3-CE (Power Integrations) - 9

InnoSwitch3-CE Applications Example
C4 2.2 nF 250 VAC 1 FL1
12 V, 3 A TP1
D3 R4 DFLR1200-7 100 kΩ C5 C6 200 V 1% C7 R1 3 FL2 470 µF 470 µF R6 470 pF 100 kΩ 16 V 16 V 2.00 MΩ R5 C8 R2 1% 20 Ω 1 nF 390 Ω R3 D1 VR1 32 Ω DL4007 BZX79-C8V2 R8 C9 8.2 V 11.8 kΩ 330 pF BR1 R7 1% 50 V GBL06 1.80 MΩ 4 Q1 F1 600 V 1% SI4190ADY 2 A D2 1N4003 1 4 2 C2 C1 C3
90 - 264
L1 33 µF T1 100 nF 33 µF C12
VAC
20 mH 400 V EQ2506 275 VAC 400 V 2.2 µF C10 R9 25 V 1 µF RT1 2 3 47 Ω 50 V 2.5 Ω t
O
C11
S
R10 22 µF
D V FWD SR VO BP GND
5.6 kΩ 50 V
CONTROL FB S BPP IS InnoSwitch3-CE
R11 0.007 Ω C13 U1 1% L2 4.7 µF INN3166C-H102 10 µH 50 V
RTN
PI-8391-100417
TP2
Figure 10. 12 V, 3 A Charger/Adapter. The circuit shown in Figure 10 is a low cost 12 V, 3 A power supply Synchronous rectification (SR) is provided by MOSFET Q1. The gate using INN3166C. This single output design features DOE Level 6 and of Q1 is turned on by secondary-side control er inside IC U1, based on EC CoC 5 compliance. the winding voltage sensed via resistor R9 and fed into the FWD pin of the IC. Bridge rectifier BR1 rectifies the AC input supply. Capacitors C2 and C3 provide filtering of the rectified AC input and together with In continuous conduction mode of operation, the MOSFET is turned inductor L2 form a pi-filter to attenuate differential mode EMI. off just prior to the secondary-side’s commanding a new switching Capacitor C4 connected at the power supply output with input cycle from the primary. In discontinuous conduction mode of common mode choke help to reduce common mode EMI. operation, the power MOSFET is turned off when the voltage drop across the MOSFET fal s below a threshold of 0 V. Secondary-side Thermistor RT1 limits the inrush current when the power supply is control of the primary-side power MOSFET avoids any possibility of connected to the input AC supply. cross conduction of the two MOSFETs and provides extremely reliable Input fuse F1 provides protection against excess input current synchronous rectification. resulting from catastrophic failure of any of the components in the The secondary-side of the IC is self-powered from either the power supply. One end of the transformer primary is connected to secondary winding forward voltage or the output voltage. Capacitor the rectified DC bus; the other is connected to the drain terminal of C12 connected to the BPS pin of InnoSwitch3-CE IC U1, provides the MOSFET inside the InnoSwitch3-CE IC (U1). decoupling for the internal circuitry. A low-cost RCD clamp formed by diode D1, resistors R3, R1, and During CC operation, when the output voltage fal s, the device will capacitor C7 limits the peak drain voltage of U1 at the instant of directly power itself from the secondary winding. During the on-time turn-off of the MOSFET inside U1. The clamp helps to dissipate the of the primary-side power MOSFET, the forward voltage that appears energy stored in the leakage reactance of transformer T1. across the secondary winding is used to charge the decoupling The InnoSwitch3-CE IC is self-starting, using an internal high-voltage capacitor C12 via resistor R9 and an internal regulator. This al ows current source to charge the BPP pin capacitor (C13) when AC is first output current regulation to be maintained down to ~3 V. Below this applied. During normal operation the primary-side block is powered level the unit enters auto-restart until the output load is reduced. from an auxiliary winding on the transformer T1. Output of the Output current is sensed between the IS and GND pins with a auxiliary (or bias) winding is rectified using diode D2 and filtered using threshold of approximately 35 mV to reduce losses. Once the current capacitor C11. Resistor R10 limits the current being supplied to the sense threshold is exceeded the device adjusts the number of switch BPP pin of InnoSwitch3-CE IC (U1). pulses to maintain a fixed output current. The secondary-side control er of the InnoSwitch3-CE IC provides The output voltage is sensed via resistor divider R4 and R8. Output output voltage sensing, output current sensing and drive to a voltage is regulated so as to achieve a voltage of 1.265 V on the MOSFET providing synchronous rectification. The secondary of the FEEDBACK pin. Capacitor C9 provides noise filtering of the signal at transformer is rectified by SR FET Q1 and filtered by capacitors C5 the FEEDBACK pin. and C6. High frequency ringing during switching transients that would otherwise create radiated EMI is reduced via a snubber (resistor R5 and capacitor C8).
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Rev. D 08/18 www.power.com Document Outline Product Highlights Description Output Power Table Pin Functional Description InnoSwitch3-CE Functional Description Primary Controller Secondary Controller Applications Example Key Application Considerations Selection of Components Recommendations for Circuit Board Layout Layout Example Quick Design Checklist Absolute Maximum Ratings Thermal Resistance Key Electrical Characteristics Typical Performance Curves InSOP-24D Package Drawing InSOP-24D Package Marking Part Ordering Table MSL Table ESD and Latch-Up Table Part Ordering Information