HX3 FAQs - KBA224063

Author: HirotakaT_91            Version: *D

 

Hardware

Question: Are there any restrictions in the powering ON/OFF sequence of VBUS_US (pin 17) in CYUSB2304-68LTXI?

Answer: VBUS_US can be powered anytime even if both 3.3 V and 1.2 V power domains are not powered. There is no specific power-up sequencing required.

Question: Are there any restrictions in the powering ON/OFF sequence of VBUS_DS (pin 18) in CYUSB2304-68LTXI?

Answer: VBUS_DS can be powered anytime even if both 3.3 V and 1.2 V power domains are not powered.

Note: The pin voltage changes take effect in Apple Charging sequence only when the Hub reads the status of the pin. The Hub reads the status at bootup and after a power cycling/reset. See AN92554 – Implementing Battery Charging Features Using HX3 for details of the Apple Charging sequence.

Question: What is the power consumption when two SuperSpeed (SS) devices and one Full-Speed (FS) device are connected to downstream (DS) ports on HX3?

Answer: The HX3 power consumption can be calculated based on the “Power Consumption” parameters listed in the HX3 datasheet (see Table 9 and Table 10). In this case, there is no pattern of “1SS + 1FS” as shown in Table 9, but you can use “1SS + 1HS” as a pattern of “1SS + 1FS” because these have the same power consumption parameters (See Table A). The configuration of “2SS + 1FS” can be considered as the same as “2SS + 1HS”. Therefore, the power consumption formula of this scenario is [d] + [g] (602.9 + 76.0 = 678.9 [mW]) is the same as that of the “2SS + 1HS” configuration.

Table A. Power Consumption Estimates for Various Usage Scenarios

Device Condition

Number and Speed of DS Ports Connected

Typical Consumption

Comments

Supply Current (mA)

Power (mW)

1.2 V

3.3 V

Active power with USB 3.0 host

1 SS + 1 HS
(equals to 1 SS + 1 FS)

218.0

103.4

602.9

[d]

Incremental active power for additional DS port

SS

39.4

8.7

76.0

[g]

Table B. Power Consumption Under Various Configurations

Configuration

Number and Speed of DS Ports Connected

Typical Consumption

Comments

Supply Current (mA)

Power (mW)

1.2 V

3.3 V

USB 3.0 4-Port Hub (USB 3.0 host)

2 SS + 1 HS devices
(equals to 2 SS + 1 FS)

257.4

112.1

678.9

[d] + [g]

                                    


Question:
What is the power consumption for 2-port HX3 hubs when there are two devices connected on the DS ports?

Answer: The power consumption of a 2-port hub is that of a 4-port hub with power saving for the two disabled ports. Therefore, the power consumption is calculated from Table 9 in the HX3 datasheet with the active power saving per disabled DS port being subtracted. For example, a USB 3.0 2-port hub (CYUSB3302/CYUSB3312) with two SS devices active on the two DS ports will have a power consumption of [a]+[g]-2*[j]=479.7 mW. See Tables A and B below.

Table A. Power Consumption Estimates for Various Usage Scenarios

Device Condition

Number and Speed of DS Ports Connected

Typical Consumption

Comments

Supply Current (mA)

Power (mW)

1.2 V

3.3 V

Active power with USB 3.0 host

1 SS

204.1

75.0

492.5

[a]

Incremental active power for additional DS port

SS

39.4

8.7

76.0

[g]

Active power saving per disabled DS port

-

10.6

9.6

44.4

[j]


Table B. Power Consumption Under Various Configurations

Configuration

Number and Speed of DS Ports Connected

Typical Consumption

Comments

Supply Current (mA)

Power (mW)

1.2 V

3.3 V

USB 3.0 2-Port Hub (USB 3.0 host)

2 SS devices

222.3

64.5

479.7

[a] + [g] – 2*[j]

 

Question: Is there any RESET timing-related restriction apart from that mentioned in the datasheet?

Answer: It is recommended to have the RESET timing of 10 ms – 15 ms where the minimum RESET timing is 5 ms as specified in the HX3 datasheet. There is no other restriction.

Question: Should I swap the SuperSpeed lines for HX3 on any of the ports when connecting to devices?

Answer: If the connector on the downstream ports or upstream port is in the form of a receptacle, then the lines need not be swapped. If the lines are being connected to a plug, then the lines need to be swapped.

For example, the CY4603 DVK has receptacles on both upstream and downstream ports, so the Tx and Rx lines are not swapped as shown below:

 

Question: Why doesn’t the Gang_mode Hub (such as CY4609 RDK) restart automatically after detecting an overcurrent condition?

Answer: It’s up to the host (operating system-dependent) to decide whether to re-power the port or not. If the hub is configured in Gang_mode, then VBUS is removed for all ports. If the hub is configured in Individual_mode (such as CY4603 DVK), then only the port which caused the overcurrent condition will be disconnected from VBUS.

Once the hub detects VBUS, the host can send a port_enable/port_power command to the hub to enable VBUS again. If the overcurrent condition has removed, the port will work fine. If the port continues to cause the overcurrent condition, the same procedure is repeated.

 

In the case of Gang_mode, because only one power switch controls all DS ports, the host may not re-power the ports. In such cases, the host waits for a user intervention to disconnect and then reconnect or power-cycle the hub.

 

Other Queries

Question: Is there a relationship between silicon Rev *A to *D of HX3 chip and Configuration A to D on HX3 Blaster Plus?

Answer: No, the chip silicon revision and HX3 Blaster Plus configuration type are not related. Any HX3 Blaster Plus configuration can work with any HX3 chip silicon revision.  

 

Related Documents

 

Datasheets:

HX3 USB 3.0 Hub Datasheet

 

Application Notes:

AN92554 - Implementing Battery Charging Features using HX3

 

Guides:

§  Blaster Plus Configuration Utility

§  CY4603 HX3 USB 3.0 Hub Development Kit

§  CY4609 HX3 USB 3.0 Hub Reference Design Kit

 

Frequently accessed Knowledge Base Articles:

§  Downloading Firmware for HX3 – KBA91657

§  FAQ on Migrating from the HX3 Rev. *A Silicon to the HX3 Rev. *D Silicon - KBA93924