Guidelines to Use PSoC 6 Internal LDO Regulator and SIMO Buck Regulator – KBA225824

Author: WangS_81           Version: **

 

Question:

What is the correct way to use internal LDO regulator and SIMO buck regulator for PSoC® 6 MCU device?

 

Answer:

In PSoC 6 devices, internal LDO and SIMO buck regulators are used for system power supply.

For PSoC 6 devices, there are internal LDO regulator and SIMO buck regulator used for system power supply. When compared with LDO, SIMO can achieve lower power consumption at the sacrifice of limited current budget. Consider the following guidelines for power management drivers while switching between two regulators:

  • The APIs Cy_SysPm_BuckEnable()Cy_SysPm_BuckEnableVoltage2() enable SIMO BUCK(BUCK1) and BUCK2, respectively. These APIs are available from the PDL integrated in both PSoC Creator™ and ModusToolbox™. LDO is always enabled by default while executing start-up code and then switches to SIMO BUCK, if SIMO BUCK is enabled in the project configuration.
  • BUCK1 is enabled when BUCK is enabled by the Cy_SysPm_BuckEnable() API.
  • Enabling BUCK2 by the Cy_SysPm_BuckEnableVoltage2()
  • There is a specified HW control bit (BUCK_OUT2_HW_SEL) for BUCK2. When this bit is set, the value of BUCK_OUT2_EN is ignored and a hardware signal is used instead.
  • Disabling of BUCK2 by theis invalid if the HW control bit is already set.
  • If AltHF(BLE ECO) is enabled in project configuration, the HW control bit will be set while executing the start-up code before main(). If BLE Component is involved without AltHF enabled, the HW control bit will be set while it calls Cy_BLE_Start()
  • Enabling BUCK through API can disable LDO automatically. But it is not possible to switch back to the LDO if the Buck has already supplied the core, and there is no API for BUCK disabling.

Note: BUCK1 and BUCK2 are the two outputs of SIMO BUCK.