Sure, you can have two voltage supply for device Vdd and resistor respectively, but need to make sure the voltage applied to resistor should not over the voltage range of Vdd.

This is a standard SPI interface ADC, there has detailed timing diagram of SPI interface in fig 5-1 & 5-2. If you are not familiar with SPI, you may refer to PIC datasheet.

充電的同時負載也在工作需考量
1. 電池在不同的充電階段, 預充(Pre-charge),定電流 (constant current) 及定電壓(constant volatge)充電三個階段, 其充電電流大小會隨不同的充電階段而改變(此電流由充電IC控制), 所以假設負載電流維持恆定則充電電流值為從電源供應器流進電池的電流減去負載電流, 所以只有在定電流充電階段淨充電電流為正, 定電壓及預充階段淨充電電流為負(電池為淨放電), 所以無法將電池充飽.

2. MCP7386x & MCP7384x內含安全充電計時器, 當充電時間超過設定值時, 充電IC會自動將充電回路斷開以確保安全, 此時負載電流全由電池供應.

由以上分析可知, 負载和電池並聯而且同時工作時會造成電池無法充飽的現象, 至於要不要這樣用完全看系統規劃而定.

The output voltage of MCP165x can up to 100V but only one output.

Any A/D has the offset that is the nature of the A/D and the offset is independent of the amplitude of the input signal, we have many customers using MCP3201 in their applications and never get this kind of problem, please check the other portion of the circuit in your application, for example, maybe you have OP Amp as an amplifier or buffer in front of A/D, sometimes the offset is caused by OP Amp, Microchip have many good OP Amp which you can choose for your applications.

I am using a MCP3201 A/D IC for my analog input convertion. I am using a 5V supply and a 2.55V refrerence.

I found a problem with my convertion result. The result of the A/D convertion have an offset,
and the offset become bigger according to the input voltage when it become bigger.

Ex. for a 1V input the result will go approx. 1.01 V and the result will reach 2.55V if the input is about 2.50V.
Can you please tell me how to solve the offset problem?

The digitalPot is a sheet-resistor which is built of diffused p-silicon layer(PAx, PBx) and the internal switches (PWx, which contains some hundred Ohms of resistance when it is on and high impedence when it is off). So, digitalPot is a variable resistor that is right. When we try to measuring resistance between PAx-PBx, PAx-PWx and PBx-PWx of MCP42100 we need to
- Applied +2.7V to +5.5V to VDD
- VSS to ground
- /RS to VDD
- keep PAx, PBx and PWx open, no connection with any
node of the circuit

Now we can measuring resistance between PAx-PBx, PAx-PWx and PBx-PWx by the multimeter.

Please be noted that the maximum voltage which can be applied to PAx, PBx or PWx should not over the VDD, for example, VDD=3.3V, make sure that the voltage applied to PAx, PBx or PWx equal to or less than 3.3V otherwise may damage the digitalPot.

MCP23016 Applications:

- General purpose I/O expansion for I2C/SMBus applications (like driving ACPI power switches, sensors, push-buttons, keypads, LEDs & fans etc.)
- Power supply applications
- PCs, cell phones, Home Appliance and industrial applications
- Board version tracking and configuration
- Board health monitoring and status reporting
- Multi-card systems in telecom, networking, and base station infrastructure equipment
- Field recall and troubleshooting functions for installed boards

MCP1252/53 is a regulated charge pump that can be used for white LED drive in parallel, the drive capability can be up to 120mA. The control of the brightness of LED can be done through a control signal which applied to /SHDN pin. Only need a small capacitance external capacitor and no inductor is required, so it is very easy to use with no EMI issues.

For drive LED in series, we have MCP1650 boost controller, the voltage output of MCP1650 can up to 100V with 5W power output, so it is easy to drive many LEDs is series, datasheet of MCP1650 been put in Microchip's website, you can get it from website or contact Microchip Taiwan office.

We don't have specific NiMH battery charger at this moment but we have a PIC+MCP1630 solutions for NiMH battery charger, please reference to "教材及講義/2004春季研討會/AIPD New product/MCP1630" to get the presentation material.