About DRV8303's charge pump

Hello,

Could you disclose the circuit diagram of DRV8303's charge pump?
In our customer, the noise emanating from around the charge pump of DRV8303.

[condition]
 1. PVDD = 12V  --->   Noise is small
 2. PVDD = 14V  --->   Noise increase
 3. PVDD = 17V  --->   Noise is the most increase
                                However, when the PVDD is larger than 17V, the noise is reduce.
 4. PVDD = 28V  --->   Noise is most small.
                                However, when the PVDD is larger than 28V, the noise is increase.

Since the magnitude of the noise is changed by the input voltage (PVDD), we want to know the operation of the charge pump.

We believes also that there is a problem with the layout of the board,but I want to check the operation of the charge pump simultaneously.

Best regards,