Datasheet AH4930 (Diodes) - 9
| 制造商 | Diodes |
| 描述 | 3D Magnetic Linear Hall Sensor with I2C Interface |
| 页数 / 页 | 23 / 9 — AH4930. Application Information. 2.3 Wake-Up Function. 303us. time. … |
| 文件格式/大小 | PDF / 1.1 Mb |
| 文件语言 | 英语 |
AH4930. Application Information. 2.3 Wake-Up Function. 303us. time. Figure 3. Wake-Up Function. Measurements
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AH4930 Application Information
(continued)
2.3 Wake-Up Function
When upper and lower comparison threshold for each of the three magnetic channels (X/Y/Z) of wake-up function and wake-up enable are set, each component of the applied field is compared to the lower and upper threshold. Whenever one of the results is above or below these thresholds, an interrupt pulse /INT is generated. The sensor informs the microcontroller by asserting an interrupt for a certain magnetic field strength change. Only when all components of the magnetic field stay within the envelope, no interrupt signal will be provided. Note that the /INT can also be inhibited during I2C activities to avoid activated collision. A wake-up interrupt /INT is the logical OR among all wake-up interrupt envelopes of the three channels. The wake-up threshold levels will be XYZ_H/L[10:0]*2 Gauss when wake-up high/low threshold and wake-up enable are set. X/Y/Z Channel Magnetic Field (Gs) HI_THRESHOLD (Gs) LO_THRESHOLD(Gs)
303us
/INT(V)
time Figure 3. Wake-Up Function 3 Measurements
Below calculations of the magnetic flux and temperatures with 12 bit/8 bit are shown.
3.1 Calculation of the Magnetic Flux
The AH4930 provides the Bx, By and Bz signed values based on Hall probes calculated in 2’s complement. The magnetic flux values can be found in the Bx/By/Bz registers of register table. A generic example is calculated next.
Table 1 Conversion Table for 12 Bit MSB LSB Bit10 Bit9 Bit8 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit11 Bit0
-2048 1024 512 256 128 64 32 16 8 4 2 1 e.g. 1 1 1 1 0 0 0 0 1 1 1 1 Example for 12 Bit read-out: 1111 0000 1111: -2048 + 1024 + 512 + 256 + 0 + 0 + 0 + 0 + 8 + 4 + 2 +1 = -241 LSB Calculation to Gs: -241 LSB × 1 Gs/LSB = -241Gs
Table 2 Conversion Table for 8 Bit MSB Bit10 Bit9 Bit8 Bit7 Bit6 Bit5 Bit4 Bit11
-128 64 32 16 8 4 2 1 e.g. 0 1 0 0 1 1 0 1 Example for 8 Bit read-out: 0100 1101: 0 + 64 + 0 + 0 + 8 + 4 + 0 + 1 = 77 LSB Calculation to Gs: 77 LSB × 16 Gs/LSB = 1232 Gs AH4930 9 of 23 January 2025 Document number: DS46768 Rev. 1 - 2
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© 2025 Copyright Diodes Incorporated. All Rights Reserved.
(continued)
2.3 Wake-Up Function
When upper and lower comparison threshold for each of the three magnetic channels (X/Y/Z) of wake-up function and wake-up enable are set, each component of the applied field is compared to the lower and upper threshold. Whenever one of the results is above or below these thresholds, an interrupt pulse /INT is generated. The sensor informs the microcontroller by asserting an interrupt for a certain magnetic field strength change. Only when all components of the magnetic field stay within the envelope, no interrupt signal will be provided. Note that the /INT can also be inhibited during I2C activities to avoid activated collision. A wake-up interrupt /INT is the logical OR among all wake-up interrupt envelopes of the three channels. The wake-up threshold levels will be XYZ_H/L[10:0]*2 Gauss when wake-up high/low threshold and wake-up enable are set. X/Y/Z Channel Magnetic Field (Gs) HI_THRESHOLD (Gs) LO_THRESHOLD(Gs)
303us
/INT(V)
time Figure 3. Wake-Up Function 3 Measurements
Below calculations of the magnetic flux and temperatures with 12 bit/8 bit are shown.
3.1 Calculation of the Magnetic Flux
The AH4930 provides the Bx, By and Bz signed values based on Hall probes calculated in 2’s complement. The magnetic flux values can be found in the Bx/By/Bz registers of register table. A generic example is calculated next.
Table 1 Conversion Table for 12 Bit MSB LSB Bit10 Bit9 Bit8 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit11 Bit0
-2048 1024 512 256 128 64 32 16 8 4 2 1 e.g. 1 1 1 1 0 0 0 0 1 1 1 1 Example for 12 Bit read-out: 1111 0000 1111: -2048 + 1024 + 512 + 256 + 0 + 0 + 0 + 0 + 8 + 4 + 2 +1 = -241 LSB Calculation to Gs: -241 LSB × 1 Gs/LSB = -241Gs
Table 2 Conversion Table for 8 Bit MSB Bit10 Bit9 Bit8 Bit7 Bit6 Bit5 Bit4 Bit11
-128 64 32 16 8 4 2 1 e.g. 0 1 0 0 1 1 0 1 Example for 8 Bit read-out: 0100 1101: 0 + 64 + 0 + 0 + 8 + 4 + 0 + 1 = 77 LSB Calculation to Gs: 77 LSB × 16 Gs/LSB = 1232 Gs AH4930 9 of 23 January 2025 Document number: DS46768 Rev. 1 - 2
www.diodes.com
© 2025 Copyright Diodes Incorporated. All Rights Reserved.