US 4,818,895 A · Direct current sense lead

Abstract

In a circuit assembly (36) having a semiconductor chip such as a MOSFET (12) mounted on a drain terminal lead frame (6) on a ceramic substrate (4), a combined source and gate return reference jumper wire (40) is connected between a current sense lead frame (52) and a combined gate return reference and current sense lead frame (38). The jumper wire has a first middle portion (42) connected to the source pad (14) of the MOSFET chip (12), and has a second middle portion 58 connected to the source terminal lead frame (8). Direct gate return referencing is provided, minimizing inductance in the gate return which is otherwise present when the gate return current path shares a portion of the source terminal current path. Direct current sensing is also provided, and the IR drop is sensed across the section of the wire jumper between the noted first and second middle portions (42and 58), without the need of an auxiliary resistor in series with the source terminal. A gold wire (62 ) is bonded to an aluminum jumper wire (40) directly at the MOSFET source pad (14) at the noted first middle portion (42) of the wire, to provide a thermocouple thereat for direct junction temperature sensing.

Claims27

Dependent claims

In an electrical circuit assembly comprising a semiconductor chip having first, second and third terminal connection pads of given lateral size, first and second main terminals connected respectively to said first and second connection pads and providing a main current flow path through said chip, a control terminal connected to said third connection pad for controlling said main current flow, a control return reference terminal connected through a portion of said second main terminal to said second connection pad, the improvement comprising means for minimizing inductance in said control return reference terminal comprising means connecting said control return reference terminal to said second main terminal directly at said second connection pad without plural laterally adjacent bonds at said second connection pad otherwise restricting the size of terminals which can fit within said given lateral size of said second connection pad.

An electrical circuit assembly comprising:

a semiconductor chip having first, second and third terminal connection pads;
first, second and third lead frames connected respectively to said first, second and third terminal connection pads, said first and second lead frames providing main terminals for main current flow through said chip, said third lead frame providing a control terminal for controlling said main current flow;
a control return reference terminal lead frame;
a combined second main terminal jumper conductor and control return reference terminal jumper conductor comprising a single continuous conductor connected between said second main terminal lead frame and said control return reference terminal lead frame and having a middle portion connected to said second main terminal connection pad, and wherein said middle portion is the only portion of said continuous conductor carrying both control return reference terminal lead frame current and second main terminal lead frame current, to minimize inductance in said control return reference terminal lead frame.

1 more element

An electrical circuit assembly comprising:

a semiconductor chip having first and second main terminal connection pads;
first and second main terminal lead frames connected respectively to said first and second connection pads, said second main terminal lead frame being connected to said second connection pad through a jumper conductor;
current sensing means comprising means connected to said jumper conductor directly at said second main terminal connection pad and connected to said jumper conductor at a point spaced from said second main terminal connection pad by a given length of said jumper conductor therebetween, such that main current flow through said chip and said second main terminal connection pad is sensed according to the IR drop across said given length of said jumper conductor, without the need of an auxiliary resistor.

An electrical circuit assembly comprising:

a semiconductor chip having first, second and third terminal connection pads;
first, second and third lead frames connected respectively to said first, second and third terminal connection pads said first and second lead frames providing first and second main terminals for main current flow through said chip, said third lead frame providing a control terminal for controlling said main current flow;
a control return reference terminal lead frame;
a combined second main terminal jumper conductor and control return reference terminal jumper conductor comprising a single continuous aluminum conductor connected between said second main terminal lead frame and said control return reference terminal lead frame and having a middle portion bonded to said second main terminal connection pad;
a gold wire of smaller diameter than said aluminum conductor and bonded to said aluminum conductor at said middle portion to provide a thermocouple producing a Seebeck voltage which varies with temperature, to provide an accurate indication of junction temperature sensed directly at said second main terminal connection pad.

2 more elements

Dependencies are inferred from the claim text.

Direct current sense lead

Life of this patent

Direct current sense lead

Life of this patent

Abstract

Claims27