Molded power module having single in-line leads

Patent metadata

Field	Value
Publication number	US-10056893-B2
Application number	US-201615294778-A
Country	US
Kind code	B2
Filing date	Oct 16, 2016
Priority date	Oct 16, 2016
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

A power module has a lead frame, a first power chip, a second power chip, a plurality of single in-line leads, a gate drive and protection integrated circuit (IC), a plurality of bonding wires and a molding encapsulation. The first and second power chips are attached to a top surface of the lead frame. The plurality of single in-line leads has a high voltage power lead, a low voltage power lead and a plurality of signal control leads. The low voltage power lead has a lead portion and an extension portion. The gate drive and protection IC is attached to the extension portion of the low voltage power lead. The molding encapsulation encloses the first and second power chips, the extension portion of the low voltage power lead, the gate drive and protection IC, the plurality of bonding wires and at least a majority portion of the lead frame.

First claim

The invention claimed is:

1. A power module comprising:
a die paddle;
one or more power chips attached to a top surface of the die paddle;
a plurality of single in-line leads including a high voltage power lead, a low voltage power lead and a plurality of signal control leads, the low voltage power lead having a lead portion generally parallel to the high voltage power lead and an extension portion generally perpendicular to the lead portion;
a gate drive and protection integrated circuit (IC) attached to the extension portion of the low voltage power lead;
a plurality of bonding wires; and
a molding encapsulation enclosing the one or more power chips, the extension portion of the low voltage power lead, the gate drive and protection IC, the plurality of bonding wires and at least a majority portion of the die paddle;
wherein the extension portion of the low voltage power lead is between the die paddle and the plurality of signal control leads.

2. The power module of claim 1 , wherein one of the one or more power chips is an insulated-gate bipolar transistor (IGBT).

3. The power module of claim 1 , wherein a bottom surface of the die paddle is exposed from the molding encapsulation.

4. The power module of claim 3 , wherein a heat sink is directly attached to the exposed bottom surface of the die paddle.

5. The power module of claim 4 , wherein the molding encapsulation has a first and second screw mounting cutouts;
wherein the heat sink has a third and fourth screw mounting cutouts;
wherein the third screw mounting cutout is aligned with the first screw mounting cutout; and
wherein the fourth screw mounting cutout is aligned with the second screw mounting cutout.

6. The power module of claim 1 , wherein a body of the power module is of a same size of a TO247 package.

7. The power module of claim 1 , wherein the molding encapsulation is of a rectangular prism shape;
wherein the molding encapsulation has a first side surface and a second side surface opposing the first side surface;
wherein a first screw mounting cutout is near the first side surface of the molding encapsulation; and
wherein a second screw mounting cutout is near the second side surface of the molding encapsulation.

8. The power module of claim 1 , wherein the molding encapsulation has an isolation cutout between the high and low voltage power leads of the plurality of single in-line leads.

9. The power module of claim 1 , wherein a thickness of the die paddle is larger than a thickness of each of the plurality of single in-line leads.

10. The power module of claim 1 , wherein a width of the high voltage power lead is larger than a width of each of the plurality of signal control leads.

11. The power module of claim 1 , wherein a width of the lead portion of the low voltage power lead is larger than a width of each of the plurality of signal control leads.

12. The power module of claim 1 , wherein a pitch between the high and low voltage power leads is larger than a pitch between adjacent signal control leads of the plurality of signal control leads.

13. The power module of claim 1 further comprising a lead frame including the die paddle and the plurality of single in-line leads, wherein the lead frame is a dual gauge copper lead frame.

14. The power module of claim 1 , wherein the plurality of bonding wires are aluminum wires.

15. The power module of claim 1 , wherein the low voltage power lead is a single-piece constructed assembly.

16. The power module of claim 1 , wherein the low voltage power lead is a two-piece constructed assembly and wherein the extension portion of the low voltage power lead has a first portion connected to the lead portion of the low voltage power lead and a second portion separated from the first portion.

17. The power module of claim 1 , wherein the gate drive and protection IC is directly mounted on a top surface of the extension portion of the low voltage power lead;
wherein a width of the extension portion of the low voltage power lead is larger than a width of the gate drive and protection IC; and
wherein a length of the extension portion of the low voltage power lead is larger than a length of the gate drive and protection IC.

18. The power module of claim 1 , wherein a pre-determined lower bound limit of a maximum vertical distance between a selected bonding wire of the plurality of bonding wires and the die paddle is a function of an insulation property of the molding encapsulation;
wherein the pre-determined lower bound limit increases as the insulation property of the molding encapsulation decreases;
wherein the pre-determined lower bound limit is three millimeters mm when a thermal conductivity of the molding encapsulation is 0.7 watt per meter kelvin; and
wherein the pre-determined lower bound limit is four millimeters when the thermal conductivity of the molding encapsulation is 0.8 watt per meter kelvin.

19. The power module of claim 1 , wherein the one or more power chips
comprises
a first power chip; and
a second power chip;

wherein the first power chip is a vertical diode having a cathode at a bottom surface of the first power chip;
wherein the cathode of the first power chip is electrically connected to the die paddle;
wherein the second power chip is an insulated-gate bipolar transistor (IGBT) having a bottom collector electrode electrically connected to the die paddle;
wherein the high voltage power lead is connected to the die paddle;
wherein the low voltage power lead is adjacent to the high voltage power lead;
wherein the plurality of signal control leads are displaced away from the high voltage power lead;
wherein the high voltage power lead and the extension portion are on opposite sides of the lead portion;
wherein the extension portion has
a first end; and
a second end;

wherein the first end of the extension portion is connected to the lead portion;
wherein the second end of the extension portion extends beyond an edge of the plurality of signal control leads;
wherein a first subset of the plurality of bonding wires electrically connect the first power chip and the second power chip to the low voltage power lead; and
wherein a second subset of the plurality of bonding wires electrically connect the gate drive and protection IC to the second power chip, the low voltage power lead and the plurality of signal control leads 460.

20. A power module comprising:
a die paddle;
one or more power chips attached to a top surface of the die paddle;
a plurality of single in-line leads including a high voltage power lead, a low voltage power lead and a plurality of signal control leads, the low voltage power lead having a lead portion generally parallel to the high voltage power lead and an extension portion generally perpendicular to the lead portion;
a gate drive and protection integrated circuit (IC) attached to the extension portion of the low voltage power lead;
a plurality of bonding wires; and
a molding encapsulation enclosing the one or more power chips, at least a majority portion of the extension portion of the low voltage power lead, the gate drive and protection IC, the plurality of bonding wires and at least a majority portion of the die paddle;
wherein the extension portion of the low voltage power lead is between the die paddle and the plurality of signal control leads; and
wherein an end face of the extension portion of the low voltage power lead is exposed from a side face of the molding encapsulation.

Assignees

• Alpha & Omega Semiconductor Cayman Ltd

Inventors

• Suh Bum-Seok
• Niu Zhiqiang
• Cho Wonjin
• Tran Son
• Bou James Rachana

Classifications

• H03K2017/0806

  against excessive temperature · CPC title

• H03K17/163

  Soft switching · CPC title

• H03K17/08116

  in composite switches (H03K17/0812, H03K17/0814 take precedence) · CPC title

• H03K17/041 Primary

  without feedback from the output circuit to the control circuit {(H03K17/0403, H03K17/0406 take precedence)} · CPC title

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title