关于MC33PT2000AF相关内容询问

[Doublemint]

HI，NXP工程师：

关于MC33PT2000AF芯片的充电泵、信号输入和外部VCCP供电的问题：

1. 充电泵的工作原理与占空比：

   • 芯片内部的充电泵依赖于Vboost提供的电压来维持100%占空比。我想了解占空比的具体含义：它是指主控芯片向MC33PT2000AF芯片的StartX引脚施加的信号占空比，还是指该芯片在执行电流闭环操作时的占空比？

2. StartX引脚的信号要求：

   • 对于英飞凌Aurix系列单片机的GPIO和GTM两种输出方式，哪一种更适合用于激活MC33PT2000AF芯片的控制器通道？这两种信号是否都可以使芯片正常工作？

3. 多芯片应用中的Vboost连接：

   • 如果使用多个MC33PT2000AF芯片来满足对控制气缸数量的需求，所有芯片的Vboost引脚是否应该以相同的方式连接？或者只需要连接其中一个Vboost引脚？

4. 外部VCCP供电的具体要求：

   • 数据手册说24V系统，需要使用外部VCCP供给，否则使用内部会有较大损耗。但是它数据手册并没有说明需要使用的电压值是不是仍然是7V，推荐使用的电容器数值是否没有变化？针对这一点需要询问。
     2024.01.02

[wuliang]

关于startx引脚信号要求，接到aurix的gpio还是gtm。应该要接gtm的atom，只有这样才能使用atom的定时中断功能，实现6缸的时序以及脉冲长度（即喷油时长）控制，普通gpio无非实现的。此处我已经使用tc3xx实现。start的拉低时间即为一个喷油peak，hold等整个喷油周期的时间。

[JozefKozon · Accepted solution]

Dear Junyao,

The working principle and duty cycle of the charge pump :

• The charge pump inside the chip relies on the voltage provided by Vboost to maintain 100% duty cycle. I would like to know the specific meaning of duty cycle: does it refer to the signal duty cycle applied by the main control chip to the StartX pin of the MC33PT2000AF chip, or does it refer to the duty cycle of the chip when performing a current closed-loop operation?

[A] The meaning of the charge pump 100% duty cycle, means, that the charge pump is capable to work with 100% duty cycle. It doesn't mean, that it will work with 100% duty cycle. The actual duty cycle depends on your configuration. 

Signal requirements for the StartX pin :

• Regarding the two output modes of GPIO and GTM of the Infineon Aurix series microcontroller, which one is more suitable for activating the controller channel of the MC33PT2000AF chip? Do both signals make the chip work properly?

[A] Unfortunately we cannot support you for the Aurix MCUs even if we want to. We do not have access to Infineon's documents. For recommended connection of the START1 through START7 pins, you can refer to our KITPT2000FRDM6C + to FRDM-KL25Z MCU board. 

Please refer to the KITPT200FRDM6C User Guide.

Vboost connections in multi-chip applications :

• If multiple MC33PT2000AF chips are used to satisfy the need to control the number of cylinders, should the Vboost pins of all chips be connected in the same way? Or just need to connect one of the Vboost pins?

[A] The Vboost capabilities are defined for only one PT2000 connected. If more, than one PT2000 is connected, then you need to connect Vboost for each PT2000 separately.

Specific requirements for external VCCP power supply :

• The data sheet says that a 24V system needs to use an external VCCP supply, otherwise there will be greater losses when using it internally. However, its data sheet does not indicate whether the voltage value to be used is still 7V. Has the recommended capacitor value remained unchanged? Questions need to be asked about this.

[A] Yes, the external voltage applied to the VCCP pin must be 7V. Please refer to the note 2. and to section 6.1.4.2 in the MC33PT2000 datasheet. 

With Best Regards,

Jozef

[Doublemint]

"Okay, thank you very much for your help with my project. Perhaps my second question was a bit too abstract, as you might be missing some relevant information. However, I'd still like to ask one more thing - does the STARTX pin simply require a sustained high level for a certain duration to operate? Can this be achieved with just a CMOS high level output from GPIO, or is it necessary to use PWM?"

[JozefKozon]

Dear Junyao,

the STARTx pins require sustained voltage level, no PWM is needed. But you will need an MCU to set the STARTx pins as inputs. Please see the description from an application engineer to another customer with similar question.

DESCRIPTION

If the MCU is connected to the kit then the MCU by default will drive the STARTx pin. If customer want to force them at 5V meaning that they drive them externally without an MCU then they need to have the MCU set as inputs pin to avoid a "fight"between MCU and their external equipment.

With Best Regards,

Jozef