Magnetic field sensor with improved sensitivity to magnetic fields

Patent metadata

Field	Value
Publication number	US-9291478-B2
Application number	US-201213484640-A
Country	US
Kind code	B2
Filing date	May 31, 2012
Priority date	May 31, 2012
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

A magnetic field sensor has internal power supply generating circuits to generate a higher operating voltage for a magnetic field sensing element, resulting in a magnetic field sensor with improved sensitivity to magnetic fields.

First claim

What is claimed is:

1. An electronic circuit, comprising:
a power supply input node configured to receive a power supply voltage, wherein the power supply voltage has, at different times, a range of values comprising a steady state power supply voltage value, a maximum power supply voltage value above the steady state value, and a minimum power supply voltage value below the steady state value;
a peak voltage suppression circuit having an input node and an output node, wherein the input node of the peak voltage suppression circuit is coupled to the power supply input node, wherein the peak voltage suppression circuit is configured to suppress the maximum value of the power supply voltage, wherein the peak voltage suppression circuit is configured to generate a suppressed voltage at the output node of the peak voltage suppression circuit, wherein the suppressed voltage has a maximum value below the maximum value of the power supply voltage;
a voltage conversion circuit having an input node and an output node, wherein the input node of the voltage conversion circuit is coupled to the output node of the peak voltage suppression circuit, wherein a converted voltage is generated at the output node of the voltage conversion circuit, wherein, when the power supply voltage is at the minimum power supply voltage value, the converted voltage has a minimum converted voltage value higher than the minimum power supply voltage value;
a sensing element coupled to receive a sensing element current or a sensing element voltage derived from the converted voltage, wherein a sensitivity of the sensing element is related to the value of the converted voltage.

2. The electronic circuit of claim 1 , wherein the sensing element comprises a magnetic field sensing element.

3. The electronic circuit of claim 2 , wherein the converted voltage has a substantially constant value throughout the range of power supply voltages, wherein the voltage conversion circuit comprises:
a linear voltage regulator having an input node and an output node, wherein the linear voltage regulator is configured to generate a linearly regulated voltage at the output node of the linear regulator, wherein the input node of the linear voltage regulator is coupled to the output node of the peak voltage suppression circuit; and
a DC-DC converter having an input node and an output node, wherein the input node of the DC-DC converter is coupled to the output node of the linear voltage regulator, wherein the output node of the DC-DC converter is coupled to the output node of the voltage conversion circuit, and wherein the DC-DC converter comprises a switching circuit.

4. The electronic circuit of claim 3 , wherein the peak voltage suppression circuit and the linear voltage regulator are conjoined in a common peak voltage suppressed linear voltage regulator arrangement.

5. The electronic circuit of claim 3 , wherein the steady state value of the power supply voltage is between about 12 volts and about 14 volts, wherein the maximum value of the power supply voltage is above fifty volts, and wherein the minimum value of the power supply voltage is about four volts.

6. The electronic circuit of claim 5 , wherein the linearly-regulated voltage is about three volts.

7. The electronic circuit of claim 6 , wherein the DC-DC converter comprises a charge pump.

8. The electronic circuit of claim 7 , further comprising:
a semiconductor substrate, wherein the linear regulator comprises a plurality of active electronic components formed upon the semiconductor substrate, wherein the charge pump comprises a plurality of active electronic components formed upon the semiconductor substrate, and wherein the sensing element is formed upon the semiconductor substrate;
a lead frame coupled to the semiconductor substrate, wherein the lead frame comprises a plurality of leads; and
a mold compound encapsulating the semiconductor substrate and covering a portion of the lead frame, wherein the charge pump comprises a discrete capacitor, wherein the discrete capacitors is electrically coupled to the semiconductor substrate and encapsulated by the mold compound.

9. The electronic circuit of claim 8 , wherein the discrete capacitor is directly coupled to the lead frame apart from the semiconductor substrate.

10. The electronic circuit of claim 8 , wherein the discrete capacitor comprises a plurality of layers upon the substrate.

11. The electronic circuit of claim 6 , wherein the DC-DC converter comprises a switching regulator.

12. The electronic circuit of claim 11 , further comprising:
a semiconductor substrate, wherein the linear regulator comprises a plurality of active electronic components formed upon the semiconductor substrate, wherein the switching regulator comprises a plurality of active electronic components formed upon the semiconductor substrate, and wherein the sensing element is formed upon the semiconductor substrate;
a lead frame coupled to the semiconductor substrate, wherein the lead frame comprises a plurality of leads; and
a mold compound encapsulating the semiconductor substrate and covering a portion of the lead frame, wherein the switching regulator comprises a discrete electronic component, wherein discrete electronic component is electrically coupled to the semiconductor substrate and encapsulated by the mold compound.

13. The electronic circuit of claim 12 , wherein the discrete electronic component is directly coupled to the lead frame apart from the semiconductor substrate.

14. The electronic circuit of claim 12 , wherein the discrete electronic component comprises a discrete capacitor comprising a plurality of layers upon the substrate.

15. The electronic circuit of claim 3 , wherein the DC-DC converter comprises a charge pump.

16. The electronic circuit of claim 15 , further comprising:
a semiconductor substrate, wherein the linear regulator comprises a plurality of active electronic components formed upon the semiconductor substrate, wherein the charge pump comprises a plurality of active electronic components formed upon the semiconductor substrate, and wherein the sensing element is formed upon the semiconductor substrate;
a lead frame coupled to the semiconductor substrate, wherein the lead frame comprises a plurality of leads; and
a mold compound encapsulating the semiconductor substrate and covering a portion of the lead frame, wherein the charge pump comprises a discrete capacitor, wherein the discrete capacitor is electrically coupled to the semiconductor substrate and encapsulated by the mold compound.

17. The electronic circuit of claim 16 , wherein the discrete capacitor is directly coupled to the lead frame apart from the semiconductor substrate.

18. The electronic circuit of claim 16 , wherein the discrete capacitor comprises a plurality of layers upon the substrate.

19. The electronic circuit of claim 3 , wherein the DC-DC converter comprises a switching regulator.

20. The electronic circuit of claim 19 , further comprising:
a semiconductor substrate, wherein the linear regulator comprises a plurality of active electronic components formed upon the semiconductor substrate, wherein the switching regulator comprises a plurality of active electronic components formed upon the semiconductor substrate, and wherein the sensing element is formed upon the semiconductor substrate;
a lead frame coupled to the semiconductor substrate, wherein the lead frame comprises a plurality of leads; and
a mold compound encapsulating the semiconductor substrate and cove

Assignees

• Contaldo Mauricio
• Szczeszynski Gregory
• Monreal Gerardo A
• Allegro Microsystems Llc

Inventors

• Contaldo Mauricio
• Szczeszynski Gregory
• Monreal Gerardo A

Classifications

• G01R33/07

  Hall effect devices · CPC title

• G01R33/0005

  Geometrical arrangement of magnetic sensor elements; Apparatus combining different magnetic sensor types (G01R33/0206 takes precedence) · CPC title

• G01D5/145 Primary

  influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06) · CPC title