CMOS power sensor
A CMOS power sensor is disclosed in the present invention. The CMOS power sensor includes a current coil, a high voltage device circuit, and a Hall device. The current coil is fabricated during the process steps of forming gold bumps of a CMOS device. One end of the current coil is connected to a voltage source, and the other end of the current coil is connected to a load. The high voltage device circuit is connected to the voltage source. The Hall device is connected to the high voltage device circuit and induces a Hall voltage in response to the magnetic field generated by the current coil.
1. A CMOS power sensor to detect a power magnitude of a given voltage source, comprising:
a CMOS device with at least one gold bump;
a current coil fabricated during fabrication steps of forming the at least one gold bump;
wherein said current coil is connected to said voltage source and a load;
a high voltage device circuit, which is connected to said voltage source; and
a Hall device, which is connected to said high voltage device circuit and induces a Hall voltage in response to a magnetic field generated by said current coil.
2. The CMOS power sensor of claim 1 , wherein said current coil is made of gold.
3. The CMOS power sensor of claim 2 , wherein said current coil is formed by an electroplating process.
4. The CMOS power sensor of claim 2 , wherein said current coil further contains a pad layer made of TiW/Au.
5. The CMOS power sensor of claim 1 , wherein said current coil has a thickness of between 4 μm and 20 μm.
6. The CMOS power sensor of claim 1 , wherein said high voltage device circuit works as a voltage follower.
7. The CMOS power sensor of claim 1 , wherein said Hall device is a four-well device.
8. The CMOS power sensor of claim 1 , wherein said Hall devices is an N-type MOS transistor.
9. The CMOS power sensor of claim 1 , wherein said Hall device is a P-type MOS transistor.
10. The CMOS power sensor of claim 1 , wherein said Hall device comprises:
a first terminal, which is connected to said high voltage device circuit;
a second terminal, which is connected to the ground;
a third terminal, which is connected to a first Hall probe; and
a fourth terminal, which is connected to a second Hall probe.
11. The CMOS power sensor of claim 10 , wherein said Hall voltage is determined to be a voltage difference between said first Hall probe and said second Hall probe.
12. The CMOS power sensor of claim 10 , further comprising a first buffer located between said third terminal and said first Hall probe.
13. The CMOS power sensor of claim 10 , further comprising a second buffer located between said fourth terminal and said second Hall probe.